# AC stops cooling when it rains



## qbert

I would have your contractor return and inspect and test wiring. Possible to have something bare and shorting due to water.


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## nap

can you yourself check the evap coil? If so, I would check it while this is happening. I suspect your evap coil may be freezing up when the rain acts as an additional heat transfer medium, which is more effective than the air, and causing the evap coil to freeze up.

Instead of waiting for the rain, I would think a sprinkler would simulate the rain.

a dirty evap coil will is also more prone to freezing up as well so if the evap coil is dirty, this would add to the situation.


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## Plumber101

If the breaker tripped one time I would start looking at the electrical connection between the disconnect and condenser. I would also inspect the low voltage wire from the furnace to the condenser.

When you start to inspect the electrical connection make sure you turn off power to the condenser. If the is a bare wire or short you don't want to be the newest short to ground.


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## Emfuser

Plumber101 said:


> If the breaker tripped one time I would start looking at the electrical connection between the disconnect and condenser. I would also inspect the low voltage wire from the furnace to the condenser.
> 
> When you start to inspect the electrical connection make sure you turn off power to the condenser. If the is a bare wire or short you don't want to be the newest short to ground.


I'm real good with industrial safety since I started my professional career as a nuclear power plant non-licensed operator. I basically do my own home red-tagging program, and do live-dead-live testing on electrical stuff I work on. 

I pulled the side panel off of my outside unit and I may have found some corrosion on the main power relay to the compressor, but the wiring looks good otherwise. I'll keep you all posted after I clean this bit up. I'm going to have to bring it inside.


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## Plumber101

You may have a contactor going bad


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## Emfuser

Well, that didn't change anything. The contactor works fine, the resistance across it was less than 1 ohm, and it shut clean when the demand signal to start the outside unit came on (after I had re-installed it).

The unit still is not rejecting any appreciable amount of heat, though, and thus not cooling. This is really puzzling.


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## Emfuser

nap said:


> can you yourself check the evap coil? If so, I would check it while this is happening. I suspect your evap coil may be freezing up when the rain acts as an additional heat transfer medium, which is more effective than the air, and causing the evap coil to freeze up.
> 
> Instead of waiting for the rain, I would think a sprinkler would simulate the rain.
> 
> a dirty evap coil will is also more prone to freezing up as well so if the evap coil is dirty, this would add to the situation.


The one time I crawled under the house and opened the panel on the air mover (right after I had shut the system down during one of my investigations), I found the evaporator wet but not frozen. The condensate drain line was also clear, and no water was pooling. The evap was pretty clean, also.

I really hope this doesn't come down to TEV or compressor replacement, but what gets me is the whole business about the system failing ONLY when it rains.


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## Plumber101

What I thought when I first read this thread was the maybe when weed eating you might have nicked the low voltage line and when it rains some how they are shorted together causing just enough voltage lost and not pull in the contactor.

Does the condenser come on and run when the concern is happening?

If it is

I'd want to know what the amps reading to the condenser is when this is happening. Low amps=fan running High amps=fan/compressor running

Want to know if the compressor is running or not.

To me this is an outside wiring issue


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## Emfuser

Plumber101 said:


> What I thought when I first read this thread was the maybe when weed eating you might have nicked the low voltage line and when it rains some how they are shorted together causing just enough voltage lost and not pull in the contactor.
> 
> Does the condenser come on and run when the concern is happening?
> 
> If it is
> 
> I'd want to know what the amps reading to the condenser is when this is happening. Low amps=fan running High amps=fan/compressor running
> 
> Want to know if the compressor is running or not.
> 
> To me this is an outside wiring issue


Unfortunately I do not have the inductive ammeter that the recent tech did. My multimeter can't handle that sort of amperage.

The only indicator I have whether or not it's fan or fan/compressor is the heat rejection, and that's pretty easy to tell the difference on. When the tech was out the other day and the unit was properly rejecting heat, it was drawing about 10 Amps.

I think it is safe to assume that the compressor is not running, based on the lack of heat rejection. At least that's what I have to go on until I can purchase or borrow an inductive ammeter.

I'll get out there tomorrow when it's daylight and have a session with the wiring diagram, following the wiring to look for anything erroneous.


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## Emfuser

Thank you for your insight, btw.


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## biggles

doubt it is the wetness of the rain i think it is more the temperature drop with the rain cooling the condenser.might want to check the stat for comptressor on/off time adjustment...you might be short cycling the compressor after the last run and the pressures haven't equalized so it goes to restart and trips the breaker.the flag there is that the condenser fan is running but the compressor isn't... you have only one contactor that powers both on a call from the stat so the compressor is going off on internal limit with that short cycle.if your stat has no configuration for compressor on and off cycle you can add a adjustable time delay out on the condenser control wiring going in. http://bestbuyheatingandairconditio...duct_Code=REL203AA&Category_Code=r-compressor


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## hvaclover

No body get's it:huh: During a rain shower the weight of the water slows down the cond fan mtr. Cond fan is weak.


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## nap

hvaclover said:


> No body get's it:huh: During a rain shower the weight of the water slows down the cond fan mtr. Cond fan is weak.


that should not appreciable change the cooling ability of the system though since if there is that much water, the cond coils would be getting washed down with the rain as well. Additionally, it takes 1/2 day or more on non-use to rectify.


For some reason, I figured the OP knew if the compressor was running or not. Apparently my mistake. Unless you have a very quiet compressor, you should be able to tell if it is running or not.

If the comp is not running, then, to me, it could be something along the lines of what plumber was shooting at or even what biggles was aiming for.

emfuser:

can you operate the unit with the cover off and observe the compressor. Even without a ammeter, you should be able to tell if the comp starts or not.

You can place a hand on the comp and tell if it is running. Safety check possible circuit pathway for shorts first though.

If the comp is not running, you need to determine why.

Is power reaching the comp? If so, a bad comp or a bad Klixon switch or bad capacitor. Biggles hit on something there as well. If a bad comp or bad klixon, or cap, a short cycle could cause a problem along these lines. If you have any of the noted problems, a short cycle may cause overload of the comp and any of the three could cause a no comp start.



Bottom line; you need to be able to determine if the comp is running and then attempt to repeat the scenario while observing.

biggles; the fact it takes upward of 1/2 a day or so would generally remove just a simple short cycle problem that a time delay would help with. There has to be a bad part to be causing long term problem such as this.

when testing I would look for an attempt to start and then comp shut down. Then, if it attempts again in a minute or so, I would look to a capacitor or a system problem allowing too high of head pressure or even liquid slugging.

If it does not try to start, I would look towards the klixon switch.


if all else fails; call an AC guy that knows more than simple gauge pressures. A "tech" that knows there is a problem under certain situations and only checks while things are expected to be working normally and leaves when things appear to be fine is not a tech.


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## Plumber101

hvaclover said:


> No body get's it:huh: During a rain shower the weight of the water slows down the cond fan mtr. Cond fan is weak.


 
I thought of the Been but I would think that it would have to be reduced by atleast 25% of more rpm to see what no cooling.

I mean I have seem as I'm sure you have seen where a condenser coil is so plugged that air flow is reduced but it still cools a little.

I'd like to put a set of gauges on and so the sprinkler thing someone here proposed


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## Emfuser

nap, Thanks for the excellent post. 

Not surprisingly, I got up this morning, flipped the AC switch to "cool", and the AC is working again (after being off for more than 12 hours overnight). So now I'm back to having a working system that I know will cease to cool the air as soon as it rains again (I live in South Carolina, so it can be almost daily at this time of year). 

Is "klixon" a colloquial name for the solenoid-driven relay that feeds main power to the outside unit, off of the nearby breaker? 

Other information that may be of use: This tends to happen while the system is in operation. As in the system will be running, a short strong rain comes through, and the system continues to run, but is producing warm air after not too long. The next time it rains when I'm home, I'll verify this.

In the time span of about a year or so, the breaker has only tripped twice, and it was the one labeled as "AC" (vs heater) which is actually on a breaker panel right next to the air handler under the house. 

The lazy tech over here the other day noticed that, when the system was turned on, that it immediately went into delay (vs coming on immediately) when switched to "cool", even after the system had been shut off for hours, and that there was probably something unusual with my thermostat wiring or settings. I'm not sure if this is relevant, but I'll just put it out there. 

Also, the electrical components mounted in the controls space on the outside unit were well-shielded from non-vaporous moisture, were dry when I took the panel off, and the components themselves looked to be in great shape. I couldn't see any capacitor swelling or leakage, nor any cold or sloppy looking solder joints, nor any rusty connectors or that sort of thing. It was remarkably unremarkable. 

*Thanks again for your help, everyone. I really appreciate it.* :thumbup:

I know this is an odd problem. Nap, I will use your advice as a guide to check some stuff the next time this happens, as it has been happening quite reliably. I will, in the mean time, contact some different local HVAC contractors to see if they'll come out and help me troubleshoot this, rather than doing what the last tech did, which wasn't much. 

I'll keep you all updated as I learn things and am always welcoming to new information.


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## nap

a klixon switch is the a mechanical overload that is attached to the compressor. It reacts to heat or by being heated. Some are visable on the outside of the comp case. Some are not.

they are quite similar to the thermal switches found in a furnace for high temp cut in and low temp cut out of the fan.

when the comp is overloaded, there is excess current draw and the motor for the comp heats up. This then causes the klixon to trip out. If it does not reset as it should or if it is weak, it would cause the comp to stay off beyond when it would normally reset or it could trip too quickly.

as to the time delay; not unusual. Some units delay every time they start. Some delay only when restarted within a determined period of time of shutdown. I would not be overly concerned unless it could be proven that it was simply causing the comp to never start for some reason. So, a question to that; when in delay, is the fan delayed too or just the comp? If it is fan also, this would remove the delay as a problem since the fan is running even when having this problem.

If it is comp only, then more investigation is needed. 

to the capacitor; caps don't alway look bad when they go bad. Sometimes the simply lose capacity. Unless you have a cap checker on your meter, you will not be able to determine if this is the case. You can do a basic check on a cap with a voltmeter and an ohmmeter but that will not provide an actual cap rating, which would be needed here, IMO.


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## nap

I have one more bit of advice:


umbrella:laughing:


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## Emfuser

I've considered that too.:blush:

In the mean time, I'll check out your suggestions. Thanks.


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## hvaclover

nap said:


> a klixon switch is the a mechanical overload that is attached to the compressor. It reacts to heat or by being heated. Some are visable on the outside of the comp case. Some are not.
> 
> they are quite similar to the thermal switches found in a furnace for high temp cut in and low temp cut out of the fan.
> 
> when the comp is overloaded, there is excess current draw and the motor for the comp heats up. This then causes the klixon to trip out. If it does not reset as it should or if it is weak, it would cause the comp to stay off beyond when it would normally reset or it could trip too quickly.
> 
> as to the time delay; not unusual. Some units delay every time they start. Some delay only when restarted within a determined period of time of shutdown. I would not be overly concerned unless it could be proven that it was simply causing the comp to never start for some reason. So, a question to that; when in delay, is the fan delayed too or just the comp? If it is fan also, this would remove the delay as a problem since the fan is running even when having this problem.
> 
> If it is comp only, then more investigation is needed.
> 
> to the capacitor; caps don't alway look bad when they go bad. Sometimes the simply lose capacity. Unless you have a cap checker on your meter, you will not be able to determine if this is the case. You can do a basic check on a cap with a voltmeter and an ohmmeter but that will not provide an actual cap rating, which would be needed here, IMO.


First off i don't if you are aware that a Klixon has not been used on residential compressors for the last 30 years. The OL and over temperature protection comes from a thermistor buried in the motor windings which is of the inhereant type.


Secondly the rain failing on to a condenser will hardly suffice to cool the discharge gas going into the condenser. Water cooled pkg ac units measure water flow in gallons per minute to cool the compressor and the condenser. 

No normal rain fall is going to suffice cooling a forced air condenser.

And further more the majority of the rain will flow over the the condenser fins with very little coming in connect with copper tubing. In fact the rain running down the the finned surface will act as eliminators do in an evaporative condenser and try to re-evap the water, which can not be accomplished as the RH is at 100%.

A borderline condenser fan motor is a very likely candidate. It will stick when over heated and after being off as the OP describes will operat normally.

Why does it do it on a rainy day but not on a sunny hot day?

Amp draw. Running while the rain falls forces the fan to work harder and grow hot. And some condenser fan motors are overload protected by a Klixon or some other type or brand of like protection.

Klixons were famous for cracking the bi-metal of the motor they protected
and would operate intermittently. But again I must reiterate that compressor for residential comfort cooling do not use Klixons.

Until the OP get's a confirming opinion none of us will know for certain what the problem actually is. But some of the opinions set forth here will be much closer than others.


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## nap

clover, point out the thermistor in this unit:

ac unit

there is none of the optional wirings installed.


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## nap

> =hvaclover;287300]First off i don't if you are aware that a Klixon has not been used on residential compressors for the last 30 years. The OL and over temperature protection comes from a thermistor buried in the motor windings which is of the inhereant type


.
what the heck is "inhearant"?



> Secondly the rain failing on to a condenser will hardly suffice to cool the discharge gas going into the condenser. Water cooled pkg ac units measure water flow in gallons per minute to cool the compressor and the condenser.


a sprinkler seems to work fine. Maybe that is more water than when it rains, :laughing:



> No normal rain fall is going to suffice cooling a forced air condenser.


but it will slow a fan? and that fan being slow will cause the unit to not cool for 12 hours? as in total loss of cooling?



> And further more the majority of the rain will flow over the the condenser fins with very little coming in connect with copper tubing.


 I suggest you have no idea what the fins are even for if you say things like this. Contact with the tubes is irrelevent. The fins radiate the heat.



> In fact the rain running down the the finned surface will act as eliminators do in an evaporative condenser and try to re-evap the water, which can not be accomplished as the RH is at 100%.


Uh, ya, sure, whatever you say. Water is a much more efficient means of thermal transfer than air. Evaporation is not needed here.



> A borderline condenser fan motor is a very likely candidate. It will stick when over heated and after being off as the OP describes will operat normally.


the only thing we know is the fan does not stop yet you maintain that it slowing, an unperceptable amount by the owner, that it would stop all cooling for 12 hours.




> Why does it do it on a rainy day but not on a sunny hot day?


suggestions were given. read them.



> Amp draw. Running while the rain falls forces the fan to work harder and grow hot. And some condenser fan motors are overload protected by a Klixon or some other type or brand of like protection.


Ya, and if a Klixon or some other type of overload tripped, the fan would stop running. That is the one thing we know for sure is NOT happening.



> Klixons were famous for cracking the bi-metal of the motor they protected
> and would operate intermittently.


 cracking the bi-metal of the motor???? I can understand if you said, the bimetal thermal strip of the Klixon switch cracked and thereby causing intermittant and undependable operation but you said the metal of the motor cracked. I think you arecracked.



> But again I must reiterate that compressor for residential comfort cooling do not use Klixons.


Take a look at the pic and get back to me.




> Until the OP get's a confirming opinion none of us will know for certain what the problem actually is


Duh!!!

.


> But some of the opinions set forth here will be much closer than others.


Obviously and I would bet I know whose is nowhere near close (clover)


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## SKIP4661

My two cents, When it rains heavily, it wets the condensing coil dropping the pressure in the system. If the system is overcharged with freon the condenser may flood and slug the compressor with liquid refrigerant. The slugging overloads the compressor and the compressor shuts down on the internal overload protector. The overload may be faulty and sticks open and stays open until all of the heat is gone from the compressor. Could also be a weak capacitor or a combination of both. Just my two cents.


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## Yoyizit

*one ohm?*

Less than 30 mV across closed relay contacts at rated current is good, over 100 mV is bad.


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## yuri

Skip, FYI and others the overload is a heat only activated device and trips when the unit is run out of freon and grossly overheated. Overload/overcurrent protection is done by the cicruit breaker. Slugging will wreck the valves and it won't ever pump properly again. Just trying to be educational. OP needs to by a amprobe clamp around the wire meter and check the amps when he thinks it is not cooling and let us know if the compressor is drawing amps. The cond fan motor draws very little. Just finished the mystery of the backwards running cond fan motor and now we have this one. Interesting.:detective:


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## nap

yuri said:


> Skip, FYI and others the overload is a heat only activated device and trips when the unit is run out of freon and grossly overheated.


I have had them trip on hard start situations where there most definitely was not a lack of freon.


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## hvaclover

what the heck is "inhearant"?
_*
I misspelled** inherent*_. _*It is(as applies here) the ability to sense amperage and *_*heat and open to protect to protect the compressor from damage.*

a sprinkler seems to work fine. Maybe that is more water than when it rains,

_*A sprinkler passes more water than rain. When it rains it is always less than an inch. When we get over five inches it causes floods.When was the last rain fall you saw that came down at the same pressure the city pumps water to your home. A sprinkler moves a lot more water than a normal rain fall.

That was a bad comparison you made


*_but it will slow a fan? and that fan being slow will cause the unit to not cool for 12 hours? as in total loss of cooling?


*Either you are a DIY or you have not done much *_*hvac work or you just like blowing smoke. 

You cheery picked my last statement by leaving out the key phrase of the "weak condenser fan motor". Yes a rain will cause a weak motor to draw more amps and over heat and cut out (stop) on overload if it's so equipped.

If the condenser fan motor itself has a weak bimetal OL it could remain off for twelve hours as the weak or cracked bimetal would take that long to reset.







*_clover, point out the thermistor in this unit:








v
I suggest you have no idea what the fins are even for if you say things like this. Contact with the tubes is irrelevent. The fins radiate the heat.

_*If contact is irrelevent then the fins are useless. (BTW the fins don't radiate heat, that would make it a "static" or a plain air cooled condenser, not forced air. The fins job is to add more surface area to allow more heat exchange then a bare coil alone would allow. So I know very well wherefore i speak.

My statement said that the water would take the least line of resistance and flow down face of the fins and do no useful cooling.


*_Uh, ya, sure, whatever you say. Water is a much more efficient means of thermal transfer than air. Evaporation is not needed here.

_*Water would be a more efficient heat transfer medium in the eqipment designed for it.
And you missed the point on evaporation completely. I said (even if you didn't get the point) that the fowing water would not have any beneficial effect on condensing the liquid refrigerant because the evaporative effect that MIGHT have occured would not be able to manifest it self because the RH is 100% as it was raining.This disallows the air from absorbing the water and kills any evaporative cooling.

I refer you to "Evaporative Condensers" if you need more guidence.



*_cracking the bi-metal of the motor???? I can understand if you said, the bimetal thermal strip of the Klixon switch cracked and thereby causing intermittant and undependable operation but you said the* metal of the motor cracked. I think you arecracked.*


Following is what I actually wrote..
*
Klixons were famous for cracking the bi-metal of the motor they protected* and would operate intermittently. 

this the lie you wrote:
_*
cracking the bi-metal of the motor???? I can understand if you said, the bimetal thermal strip of the Klixon switch cracked and thereby causing intermittant and undependable operation but you said the metal of the motor cracked. I think you arecracked.


*_I think i have proved my point. You obviously lack a full set of skills so you like to blow smoke.


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## yuri

Thanks Nap and others. I have been in this biz a LONG time but definitely have not seen it all. Don't seem to have too many hard start conditions where I am but I have heard that is a problem with some TX valves and scroll compressors. Most manufacturers have accessory hard start kits with potential relays for that issue. Only internal overload trips I have had where from heat, but amperage creates heat. Always seems to lock the rotor and trip the circuit breaker IF it is properly sized, some are not. Good to share info with others.


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## hvaclover

yuri said:


> Skip, FYI and others the overload is a heat only activated device and trips when the unit is run out of freon and grossly overheated. Overload/overcurrent protection is done by the cicruit breaker. Slugging will wreck the valves and it won't ever pump properly again. Just trying to be educational. OP needs to by a amprobe clamp around the wire meter and check the amps when he thinks it is not cooling and let us know if the compressor is drawing amps. The cond fan motor draws very little. Just finished the mystery of the backwards running cond fan motor and now we have this one. Interesting.:detective:


Yuri

Thanks for that. I stand corrected.I was thinking of a fractional hp refrig comps that are amperage and heat sensitive.


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## yuri

Usually it trips the circuit breaker as they heat up VERY fast/designed to trip VERY fast and the overload takes longer, but it could go first if the breaker or fuse is too big. Have not seen a backwards running cond fan but now I know what to look for if it happens. A blob of silfoss from a poor welder can do wonders to a RFC control when it floats around. Now that was a strange intermittent problem. Eventually blew the compressor from excessive relief valve popping.


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## Emfuser

Well, yesterday the unit stopped cooling when humidity increased, but before it actually rained.

Fired it up this morning, working as it usually does when it sits all night. Today, it ran cold all day long, only to stop cooling in the late afternoon. No change in humidity, no rain in sight.

Of course, the contractor whom I contacted yesterday didn't get back to me today.

*sigh* The mystery continues...


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## hvaclover




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## Emfuser

ahahahahahahaha :laughing:


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## micromind

When the cooling stops, is the same amount of air coming out of the ducts as usual? Do you live in a high-humidity area? 

What I'm stabbing at here is the possibility of low refrigerant causing the indoor coil to ice up enough to block airflow. 

Rob


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## nap

micromind said:


> When the cooling stops, is the same amount of air coming out of the ducts as usual? Do you live in a high-humidity area?
> 
> What I'm stabbing at here is the possibility of low refrigerant causing the indoor coil to ice up enough to block airflow.
> 
> Rob


I suggested that way back in post 3 and got this response:



> The one time I crawled under the house and opened the panel on the air mover (right after I had shut the system down during one of my investigations), I found the evaporator wet but not frozen. The condensate drain line was also clear, and no water was pooling. The evap was pretty clean, also.


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## micromind

Sorry, I must have missed that one. A lot to read!

Rob


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## Emfuser

micromind said:


> Sorry, I must have missed that one. A lot to read!
> 
> Rob


Feel free to join in. The unit cooled for 1hr45min this morning before going warm.

Today it's supposed to crack 100 degrees.


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## nap

I wasn't trying to shy him away. I was just letting him know that you stated the coil is not freezing over but honestly, I really think his suggestion may have merit.

Is the airflow diminished when it goes to warm?


Since it is going to be so hot today, try this:

run until it stops cooling; set the thermostat to fan only and let it run for 1/2 to an hour. set it back to AC and see what happens. If the evap coil is freezing up, this should allow the thing to thaw and cool again.


also, the refrig lines; is the low pressure line icing up at all? Another sign that MM's suggestion is the correct one.

also, can you tell if the compressor is running? Most units sound different when the comp is running and when just the fan is running. I know you don't have an ammeter to check but try listening to the thing. If nothing else, listen now while it is not cooling and then, when it cools again, listen to see if you can discern any difference.


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## Emfuser

A competitor's tech is on the way out today. We'll get to the bottom of this and I'll let you all know what we find.


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## hvaclover

Damn Fat Eddy gets around.


A


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## Emfuser

And the winner (if you want to call it that) is... COMPRESSOR DEGRADATION AND THERMAL OVERLOAD! 

Unsurprisingly, the unit decided to work again not 5 min after their central office called and told me the tech was on the way. He showed up, I told him my story, and he got to looking. We got as far as cutting power to the outside unit (opening the breaker), pulling the fan, and checking the compressor. It was hot. When I told him that it had only been running for 20 min or so, he said yes, this is definitely the culprit. The compressor is failing, and hitting its internal thermal overload. The reason it was happening noticeably when it rains is because of the increased condensation loading on the system combined with the normal load it was already struggling to maintain. Rain just happened to be what pushed it over consistently. Now it's just too strained to even handle load on a normal summer day.

We sat there and watched the amp draw on the unit climb. In the mean time, I'm spraying the compressor down every hour or so, but it's a compensatory action on a failing unit that eventually is just gonna bite the dust.

If the compressor is still under warranty (doubtful), then it'll be ~$1100. If not, then replacement for $1900. 

Wheeeee...


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## hvaclover

hmmm......you got a pretty good handle on hvac terminology.

If that comp was weak then it would die on hot days too.


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## Emfuser

hvaclover said:


> hmmm......you got a pretty good handle on hvac terminology.
> 
> If that comp was weak then it would die on hot days too.


Terminology comes from being an engineer. I work at a nuclear power plant as an engineer, so I'm quite familiar with the industrial chilled water systems that have different heat exchanger designs (refrigerant used to chill water which either chills equipment or goes through another heat exchange with air), but not these refrigerant driven residential units. Getting into this material takes me back into my favorite subjects of thermodynamics & heat transfer.

The comp has been dying on hot days lately, as it has been hotter than when I first started the thread. Today's high: 103


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## hvaclover

I'm skeptical. You pulled the fan to to take an amp draw on the comp?


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## Emfuser

hvaclover said:


> I'm skeptical. You pulled the fan to to take an amp draw on the comp?


No, we pulled the fan so that we could place our hands on the compressor. 

The tech left his amprobe on the power lines.


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## hvaclover

So you read the amp draw with the fan pulled and the comp running while you felt the comp dome?


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## Emfuser

hvaclover said:


> So you read the amp draw with the fan pulled and the comp running while you felt the comp dome?


No, we shut the power off to the unit to pull the fan, as it would have been unsafe to lift the fan out (it was attached to the top grating) while it was running and stick our hands down there. The amprobe was simply left on the line for sake of convenience, not to read while we lifted the fan and put our hands on the compressor.

The increasing amp draw was noticeable when the unit was running.


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## SKIP4661

Emfuser said:


> No, we shut the power off to the unit to pull the fan, as it would have been unsafe to lift the fan out (it was attached to the top grating) while it was running and stick our hands down there. The amprobe was simply left on the line for sake of convenience, not to read while we lifted the fan and put our hands on the compressor.
> 
> The increasing amp draw was noticeable when the unit was running.


When the Amp draw was increasing was the fan running on the unit or was it disconnected


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## Emfuser

SKIP4661 said:


> When the Amp draw was increasing was the fan running on the unit or was it disconnected


Running and properly installed. The tech noted that the amp draw already seemed high.


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## SKIP4661

Did he attach his guages to the unit and determine the superheat or subcooling? I am curious as to what the pressures were.


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## Emfuser

skip4661 said:


> did he attach his guages to the unit and determine the superheat or subcooling? I am curious as to what the pressures were.


85/225


----------



## SKIP4661

The pressures look fairly normal. A weak capacitor will cause a motor to overheat after running for a while. I don't remember reading that this was checked.


----------



## nap

SKIP4661 said:


> The pressures look fairly normal. A weak capacitor will cause a motor to overheat after running for a while. I don't remember reading that this was checked.


can you explain how that can be if this is only a single cap motor? Or is it?

I do not believe we know this, yet.


----------



## SKIP4661

nap said:


> can you explain how that can be if this is only a single cap motor? Or is it?
> 
> I do not believe we know this, yet.


It"s been my experience that residential compressors only have one cap, there are some two speeds with two caps and I don't believe that is the case here.


----------



## yuri

There are some OLDER units with 2 capacitors: 1 for compressor and 1 for condensor fan motor. They are usually around 20 yrs old. 85 suction sounds too high. At that pressure the compressor is getting vapor back at 50 deg F which is not so good at cooling the compressor. The compression ratio is less than 3:1 so it sounds worn out to me. How old is this unit and what is the make and model #?


----------



## Emfuser

Heil HHP230AKA1
Serial L013660331 (November 2001)


----------



## yuri

The normal ratio of pressures I get are 65/250, 70/275. Have never seen anything higher than 70-75. The compression ratio is usually around 4:1 so I suspect your compressor is bad and overheating from high suction pressure/temp. You can wear a unit out in Florida, Texas if it runs steady and is undersized in that amount of time.


----------



## Emfuser

Between the heat and high humidity, plus everything else I've gone through on this adventure, a toasted compressor is seeming more and more likely.


----------



## nap

yuri said:


> There are some OLDER units with 2 capacitors: 1 for compressor and 1 for condensor fan motor. They are usually around 20 yrs old. 85 suction sounds too high. At that pressure the compressor is getting vapor back at 50 deg F which is not so good at cooling the compressor. The compression ratio is less than 3:1 so it sounds worn out to me. How old is this unit and what is the make and model #?


I understand the dual cap situation but in that, one part is for the fan starting circuit and the other for the comp start circuit.

the point I was after is unless the comp is a cap start /cap run (which I have never seen but I am not discounting the fact they may be out there), once the comp gets off the start winding, the cap is out of circuit and will not affect the motor current.

as to the pressures, I'll leave that to you folks.


----------



## Emfuser

Man, I was quoted $1115 for repair under warranty or $1900 for a replacement. Does that seem high?


----------



## yuri

Nap, I would recommend you study PSC Permanent Split Capacitor motors, theory. The start winding is in the circuit all the time. Don't know what the labor rates are in your area or cost of living but we would charge about $800 for a changeout.


----------



## hvaclover

:laughing:


----------



## nap

yuri said:


> Nap, I would recommend you study PSC Permanent Split Capacitor motors, theory. The start winding is in the circuit all the time. Don't know what the labor rates are in your area or cost of living but we would charge about $800 for a changeout.


this time, I will admit I am wrong. Not sure where my mind was with this. .


enjoy it hvaclover, I was wrong with this but not with yours.

How is that slow fan diagnosis shaping up there hvaclover?


----------



## Emfuser

yuri said:


> Nap, I would recommend you study PSC Permanent Split Capacitor motors, theory. The start winding is in the circuit all the time. Don't know what the labor rates are in your area or cost of living but we would charge about $800 for a changeout.


The cost of living in SC is fairly low. I'm pinging a bunch of HVAC places around here asking them what they'd charge to replace. I'll be able to get some responses from them on Monday, I'm guessing, but I figured it wouldn't hurt to ask around here.


----------



## hvaclover

This is a 12 SEER heat pump.


----------



## hvaclover

emfuser what was the amp draw? and what was the temp out side?


----------



## hvaclover

about how big is your house.


----------



## Emfuser

hvaclover said:


> emfuser what was the amp draw? and what was the temp out side?


About 9 amps as soon as the unit was on and was up to 11 fairly quickly. It was still creeping upwards the last I saw it before he took it off.

House is ~1500 sqft.


----------



## hvaclover

Emfuser said:


> About 9 amps as soon as the unit was on and was up to 11 fairly quickly. It was still creeping upwards the last I saw it before he took it off.
> 
> House is ~1500 sqft.


something is amiss. The FLA on that unit is 15.5. What was the outdoor temperature?


----------



## Emfuser

hvaclover said:


> something is amiss. The FLA on that unit is 15.5. What was the outdoor temperature?


Outdoor temp was 90+ degrees by that point.

11ish was the last reading I saw, not two minutes after it had been started, and it was climbing. The unit ran for a few hours after that, but has since quit again. I wish I had a probe and data recorder hooked up to the thing so I could tell how high the amps actually got to before it quit.

I'm spoiled on my plants computer system and data logging.


----------



## Emfuser

Nifty, I just found the replacement part sheet the previous owner left me.

Here is the digital version: http://icpindexing.mqgroup.com/documents/086477/42803310102.pdf

Looks like that Copeland compressor is 700-800 dollars.


----------



## yuri

Isn't Homer Simpson a Nuclear Plant engineer? :nuke: LOL. He's my hero.:thumbup:


----------



## Emfuser

yuri said:


> Isn't Homer Simpson a Nuclear Plant engineer? :nuke: LOL. He's my hero.:thumbup:


:whistling2:


----------



## nap

what is the model of your unit emfuser? The literature lists several different units specs.


----------



## Emfuser

Emfuser said:


> Heil HHP230AKA1
> Serial L013660331 (November 2001)





nap said:


> what is the model of your unit emfuser? The literature lists several different units specs.


Page 4 accosts you, sir. :jester:


----------



## Plumber101

Am I reading the model right a 2 tn on a 1500 sq ft house?

If so a little under sized.


----------



## Emfuser

Plumber101 said:


> Am I reading the model right a 2 tn on a 1500 sq ft house?
> 
> If so a little under sized.


2½ ton


----------



## Emfuser

Well, as soon as I got the unit to kick on and start blowing cold air again, I ******* engineered a setup where my hose, with a sprayer attached, continually mists the condenser unit (coils) outside.

I hope I can make this last until Monday. :blush:


----------



## yuri

I would be VERY careful about running it overloaded etc. If the compressor suffers a BURNOUT you will have an acid contaminated system which will cost twice as much to cleanup/repair. Might as well buy a new one then.


----------



## Emfuser

yuri said:


> I would be VERY careful about running it overloaded etc. If the compressor suffers a BURNOUT you will have an acid contaminated system which will cost twice as much to cleanup/repair. Might as well buy a new one then.


I see your point. My ******* mod that lets the system run longer when it might normally quit also might burn it it out.

... aw


----------



## hvaclover

Emfuser said:


> 85/225



Ok I gota say something here. 
85/225 are pressures this kind of system would see on high humidity high ambient day.

I have been a Heil dealer for years and that model hp and it's sister split ac top out at 115*f ODT. The extended performance tables show these pressures as being normal for the condition stated. 

I am not so sure what emfusor tells us is 100% accurate.

Every statement had a qualifier when a follow up question was asked to narrow the the parameters of the question.

Check the amp draw question and the other questions.

All the follow up question the OP had a qualifier for them. 


for some reason I am thinking about a childhood tale about "The Three Billy Goats Gruff" and the guy who lived under the bridge.


----------



## Emfuser

hvaclover said:


> Ok I gota say something here.
> 85/225 are pressures this kind of system would see on high humidity high ambient day.
> 
> I have been a Heil dealer for years and that model hp and it's sister split ac top out at 115*f ODT. The extended performance tables show these pressures as being normal for the condition stated.
> 
> I am not so sure what emfusor tells us is 100% accurate.
> 
> Every statement had a qualifier when a follow up question was asked to narrow the the parameters of the question.
> 
> Check the amp draw question and the other questions.
> 
> All the follow up question the OP had a qualifier for them.
> 
> 
> for some reason I am thinking about a childhood tale about "The Three Billy Goats Gruff" and the guy who lived under the bridge.


A troll? That's cute, but if you happen to live in the vicinity of Irmo, SC, then you are more than welcome to come sit in my house, that's 83 degrees at 11 PM at night (and thankfully getting cooler now), and have a beer.

I'm sorry if you're bothered by the way I write or answer questions, but I'm no troll. Who the hell would troll a forum about HVAC, anyhow? Trolls fare far better in political forums and the like where emotion can be introduced to discussion. I've been a moderator, with this same user name, at a huge, mostly pointless forum that is only entertainment for me, for a bit over seven years, and have seen many a troll. I'm not sure why you would come to that conclusion with this discussion.

Would you prefer more narrow-scoped answers to questions? I can turn off the "nuclear" fashion by which I answer questions, since it seems to bother you.


----------



## yuri

For Clover:
Thats possible but I won't stop trying to help the honest people who deserve help because of a few pretenders or gameplayers. Nobody is going to con the real techs and they know it. I imagine those pressures are possible but we never see them where I am. Doesn't get above 50% RH here. Can't imagine what that humidity load must do to the guys in Florida.


----------



## nap

has anybody read the charts emfuser provided? The pressures are quite close to the specs. Obviously without accurate temps to input, it is a guess to some extent but they are close. As to current, same thing. hvaclovers 15.5 amps is not correct. The unit emfuser has is 18.3 FLA and the comp spec is 13.6 RLA. the running amps at the given pressures are right at 11 amps +- So the amp readings the OP is getting fall in line with the rest of the readings and specs provided.


one thing that has not been answered but I presume to be true:

does the compressor drop out when it is not cooling?


If so, (and not to beat a dead horse) but a weak Klixon (mechanical internal thermal overload for those so inclined to not like the generic use of Klixon, and you know who you are) would cause the problem the OP is having. It would explain the long delay to restart as well. I do not see a thermistor used per the diagram the OP provided. It is a mechanical OL.

The part I cannot explain but another did, to an extent, is why it would happen when it rained. 

The breaker tripping is easily explained by the comp dropping out due to thermal OL and then attempting to restart before the head pressure dropped.

With a bad thermal OL, you may get inconsistent action so it may not act the same every time.

one thing you guy will have to school me on is why a bad comp would cause excess heat. I would think that if there is a high bypass, the current would be lower and the high side would be low resulting in lower comp temps.


aww heck, I give up. It's a weak condensor fan. hvaclover was right:laughing:


----------



## hvaclover

yuri said:


> For Clover:
> Thats possible but I won't stop trying to help the honest people who deserve help because of a few pretenders or gameplayers. Nobody is going to con the real techs and they know it. I imagine those pressures are possible but we never see them where I am. Doesn't get above 50% RH here. Can't imagine what that humidity load must do to the guys in Florida.



I am only stating what the data says. The data does not lie. I have the spec sheet in my dealer manual in front of me.I have been doing Heils since '87 and I have seen these condition several times.

He said the the ampdraw was 9 then 11. Then changed that too when i posted the FLA was 15 Amps.

C'mon! 87/225 90* ODT! That pump would be doing around 14. amps according to my own invoices I looked up and the tech sheet..


----------



## Emfuser

nap said:


> has anybody read the charts emfuser provided? The pressures are quite close to the specs. Obviously without accurate temps to input, it is a guess to some extent but they are close. As to current, same thing. hvaclovers 15.5 amps is not correct. The unit emfuser has is 18.3 FLA and the comp spec is 13.6 RLA. the running amps at the given pressures are right at 11 amps +- So the amp readings the OP is getting fall in line with the rest of the readings and specs provided.


The statement of the amps being high are a repetition of what the visiting tech had stated. I'm not trained or educated in any detail on these sorts of systems, so I can only relay their stated perception as to something being high or not. Since I don't know the acronyms from the spec sheet, I can't figure everything out, and have to rely on the interpretations of you folks.




nap said:


> one thing that has not been answered but I presume to be true:
> 
> does the compressor drop out when it is not cooling?


This is something I have not been able to positively determine, as the unit has been cooling both times a tech has been here with an amprobe. I was only able to tell by trying to tell a difference in sound and heat rejection. I can feel difference in heat rejection, but can't determine much for sound changes.



nap said:


> If so, (and not to beat a dead horse) but a weak Klixon (mechanical internal thermal overload for those so inclined to not like the generic use of Klixon, and you know who you are) would cause the problem the OP is having. It would explain the long delay to restart as well. I do not see a thermistor used per the diagram the OP provided. It is a mechanical OL.


The tech I had over today spoke of an overload that is internal to the compressor, rather than a Klixon.



nap said:


> The part I cannot explain but another did, to an extent, is why it would happen when it rained.


Increased condensate loading was the explanation offered by some, and consistent with my finding of excess moisture on the evaporator when I crawled under the house to take a panel off of the air mover after it had quit early into my adventures with this problem.



nap said:


> one thing you guy will have to school me on is why a bad comp would cause excess heat. I would think that if there is a high bypass, the current would be lower and the high side would be low resulting in lower comp temps.


I would assume (and this is just the engineer in me assuming) that a failing compressor would suffer a gradual drop in efficiency, but still be pushed by the system to deliver the same cooling load, thus resulting in a net increase in energy consumption by the unit.

This is why I would love to have a data record of amp draw over time for this thing rather than these periodic, not terribly useful few data points I have. inch:


----------



## hvaclover

nap said:


> has anybody read the charts emfuser provided? The pressures are quite close to the specs. Obviously without accurate temps to input, it is a guess to some extent but they are close. As to current, same thing. hvaclovers 15.5 amps is not correct. The unit emfuser has is 18.3 FLA and the comp spec is 13.6 RLA. the running amps at the given pressures are right at 11 amps +- So the amp readings the OP is getting fall in line with the rest of the readings and specs provided.
> 
> 
> one thing that has not been answered but I presume to be true:
> 
> does the compressor drop out when it is not cooling?
> 
> 
> If so, (and not to beat a dead horse) but a weak Klixon (mechanical internal thermal overload for those so inclined to not like the generic use of Klixon, and you know who you are) would cause the problem the OP is having. It would explain the long delay to restart as well. I do not see a thermistor used per the diagram the OP provided. It is a mechanical OL.
> 
> The part I cannot explain but another did, to an extent, is why it would happen when it rained.
> 
> The breaker tripping is easily explained by the comp dropping out due to thermal OL and then attempting to restart before the head pressure dropped.
> 
> With a bad thermal OL, you may get inconsistent action so it may not act the same every time.
> 
> one thing you guy will have to school me on is why a bad comp would cause excess heat. I would think that if there is a high bypass, the current would be lower and the high side would be low resulting in lower comp temps.
> 
> 
> aww heck, I give up. It's a weak condensor fan. hvaclover was right:laughing:



I don't care what the OP posted. I have the factory spec sheets and my record from annual inspections.

18 FLA on a 2 1/2 12 SEER? More like a three ton HACO36 ten SEER.


I think the guy is skunking us. You gents believe what like but I ain't buying.

This thread has all the profile traits of a troll stringing the pros along: Long thread, super unusual problem you seldom if ever come across there's more but you guys get the picture.


----------



## Emfuser

hvaclover said:


> He said the the ampdraw was 9 then 11. Then changed that too when i posted the FLA was 15 Amps.


Started at 9 and increased to 11 within a short time span before the tech turned his attention to something else, and mine along with it. As I said before, I find this information of marginal usefulness since I would much rather have a long set of data points (say at a 60 second interval) taken as the unit runs, right up until it stops cooling. Then we could tell more definitively if the amp draw is going unacceptably high.



hvaclover said:


> C'mon! 87/225 90* ODT! That pump would be doing around 14. amps according to my own invoices I looked up and the tech sheet..


That was from the first tech that came out. I didn't ask for the numbers with the guy who was here today, but the first one left them on his invoice. Sorry for the temporal mixing of information. I can see how this gave you the impression that all the numbers came from one look at the system.


----------



## hvaclover

staying with in the boundaries of the forum rules against rough language I will respond thusly: You may post as you like but if the glove don't fit you better quit.


----------



## Emfuser

hvaclover said:


> I don't care what the OP posted. I have the factory spec sheets and my record from annual inspections.
> 
> 18 FLA on a 2 1/2 12 SEER? More like a three ton HACO36 ten SEER.
> 
> I think the guy is skunking us. You gents believe what like but I ain't buying.
> 
> This thread has all the profile traits of a troll stringing the pros along: Long thread, super unusual problem you seldom if ever come across there's more but you guys get the picture.


Ok, do you guys seriously have a problem with trolls who do that *HERE*? I can't fathom why anyone would go to such enormous trouble to intentionally bother a little forum like this one.

Really, what do you want for proof? You want me to send you scans of the invoices from the contractors? You want me to take some pictures of the unit, maybe the thermostat a few hours after the next time the unit stops cooling again? I don't know what the [email protected]*# happened to you online somewhere that makes you believe I'm doing this as a big joke, but I sure don't appreciate it. I've been nothing but polite and patient in here, and had been very appreciative of all the help, but now I'm getting accused of trolling? Really?

Sorry man, I don't know what else to tell you. If something rubs you the wrong way, then by all means, leave the thread. Your posts up until you accused me of trolling were helpful, but not so much now.


----------



## hvaclover

And another thing: If you're from NC who come you dont post with a Southern accent?:whistling2::jester:


----------



## Emfuser

hvaclover said:


> And another thing: If you're from NC who come you dont post with a Southern accent?:whistling2::jester:


I was born and raised in Indiana and have lived in *South* Carolina for 6 years.

The worst you'll ever see out of me in text is "y'all". :blush:


----------



## Emfuser

Come on... I duct-taped a garden hose with a sprayer on it onto the top of a plastic sawhorse so I can put a continuous light spray on the compressor coils and nobody wants pictures of that? 

This was inspired by the main transformer spray system at my plant.


----------



## nap

hvaclover said:


> I don't care what the OP posted. I have the factory spec sheets and my record from annual inspections.
> 
> 18 FLA on a 2 1/2 12 SEER? More like a three ton HACO36 ten SEER.
> 
> 
> I think the guy is skunking us. You gents believe what like but I ain't buying.
> 
> This thread has all the profile traits of a troll stringing the pros along: Long thread, super unusual problem you seldom if ever come across there's more but you guys get the picture.




are you stating the specs posted by the OP are not correct? He went and altered some spec sheet just to troll?


----------



## hvaclover

Sure Eddy ! Post "er up!


----------



## hvaclover

nap said:


> are you stating the specs posted by the OP are not correct? He went and altered some spec sheet just to troll?


I have the same data sheet as his model.

It is 15 tops. No 12 SEER has that amp draw(18 amps) by that model.


----------



## Emfuser

hvaclover said:


> Sure Eddy ! Post "er up!


Pic attached

Ugly, but functional.


----------



## Emfuser

hvaclover said:


> I have the same data sheet as his model.
> 
> It is 15 tops. No 12 SEER has that amp draw by that model.


Hey man, I'd be much happier if I had an amprobe setup that fed an amperage reading into a data recorder every 60 seconds. That way, questions of amperage in various operating states would be definitively answered.


----------



## nap

hvaclover said:


> I have the same data sheet as his model.
> 
> It is 15 tops. No 12 SEER has that amp draw by that model.


so you are saying the specs he provided are incorrect.

Seems like a lot of work just to troll. 


so, why don't you post your spec sheet so we can see the real specs?


----------



## Emfuser

nap said:


> so you are saying the specs he provided are incorrect.
> 
> Seems like a lot of work just to troll.
> 
> so, why don't you post your spec sheet so we can see the real specs?


I have the paper version of the sheet sitting right in front of me along with the warranty certificate, the manual for the air mover unit, etc. I just don't know half of the acronyms and terminology in this thing.


----------



## nap

Emfuser said:


> I have the paper version of the sheet sitting right in front of me along with the warranty certificate, the manual for the air mover unit, etc. I just don't know half of the acronyms and terminology in this thing.


so, by the edit notation, are we to presume you did link to the wrong specs?


----------



## Emfuser

nap said:


> so, by the edit notation, are we to presume you did link to the wrong specs?


Yeah, I linked to NHP model spec sheet when this is an HHP model. The compressor is actually the same, but the whole spec sheet is not.


----------



## Emfuser

New compressor was just installed. I wish the guy didn't have to take the old one, as I would've happily torn into it (though that would have been a challenge all its own, given the sealing) just out of technical curiosity. I'm sort of curious what happens to the thing now. Does it get recycled or rebuilt somewhere?

Anyhow, I got this done under the Heil warranty, so total cost to me, after I shopped around quite a bit for quotes, ended up being $650 for the replacement.


----------



## SKIP4661

If the compressor is still under warranty it will probably have to be returned to the mfg..


----------



## hvaclover

Emfuser said:


> Yeah, I linked to NHP model spec sheet when this is an HHP model. The compressor is actually the same, but the whole spec sheet is not.


:whistling2:Gee didn't somebody mention that already?


----------



## yuri

I ground open the welding on a small refrigerator hermetic and it cost about $30 worth of grinding wheels. That is a THICK built up weld, not worth the hassle.


----------



## hvaclover

yuri said:


> I ground open the welding on a small refrigerator hermetic and it cost about $30 worth of grinding wheels. That is a THICK built up weld, not worth the hassle.


A guy here locally used to rebuild refrigerator compressors. He used a cutting 
torch.

Only thing he could not rebuild was a Frigidaire or Whirlpool rotary. 

He would rewind bad windings windings, remake valve gaskets and rewind current relay winding to match a complete rewind of start and run winding of a stator.

He would weld the dome back on and sell it. 1/4 hp comp went for 40 bucks, 1/3 hp 45 to 55 bucks.


What blew my mind was he re built GE bread loaf comps with a condenser 
and filter drier for 55 bucks.

Guy was a motor man by trade and just decided to rebuild domestic refrig compressors.


----------



## Emfuser

Sorry for being a thread necromancer, but I figured I would update.

The compressor was replaced, and the AC works like it should most of the time. It went from being next to useless, to cooling the house reliably again. Not surprisingly, it still blows warm _for awhile_ when it rains, but eventually goes back to cool air.

So today, I borrowed a Fluke 87 V from work (don't know why I didn't think to do this before), popped the cover off of the condenser, and tested the capacitor. It's a round, dual run, 370V cap rated at 45/3. Not surprisingly, both the fan side and the compressor side showed as shorts.

A new cap is on the way.


----------



## hvaclover

You had a tech out on the possibility of motor overload. You gonna tell me he didn't check the capacitor with an analyzer?.That is text book basic for your symptoms. The greenist and worst of techs would be at least smart enough to check a capacitor.

I smell BS


----------



## yuri

The greenest and worst techs don't own an analyzer or know how to use one. Tech A, got 120 volts on both lines to the A/C, changed all the parts and it still don't run. Tech B, did you check for 240 volts. Tech A, Whatz that?

2 Brownie points for the first tech with the real answer.


----------



## hvaclover

yuri said:


> The greenest and worst techs don't own an analyzer or know how to use one. Tech A, got 120 volts on both lines to the A/C, changed all the parts and it still don't run. Tech B, did you check for 240 volts. Tech A, Whatz that?
> 
> 2 Brownie points for the first tech with the real answer.



a case of Molson says your wrong.

That's a basic function on most dmms these days. Every new hire right out of school here has a dmm with all the functions of a fluke 116.

And there is nothing complicated about it. You either read good or bad.

That should have been found by at least one of the techs who came out.


----------



## yuri

From what I am seeing they are more interested in planning their social lives and talking to their wives/girlfriends every 10 minutes on the cell phone. 

Getting old and grouchy I am, just like Yoda.:laughing:


----------



## hvaclover




----------



## hvaclover

And if it really get heated


----------



## Emfuser

hvaclover said:


> You had a tech out on the possibility of motor overload. You gonna tell me he didn't check the capacitor with an analyzer?.That is text book basic for your symptoms. The greenist and worst of techs would be at least smart enough to check a capacitor.
> 
> I smell BS


Uh, do you want me to post scans of the receipt from the work to replace the compressor or shall I attempt to photograph myself putting leads on the capacitor while taking a reading? As I've said before, if you choose to believe that this is some elaborate trolling scheme, you don't have to reply. Your responses before you became convinced that I'm a troll (and _some_ of them afterwords) were helpful and appreciated. 

Anyhow, thought the same thing as you, but still felt stupid for not putting my crappy wal-mart multimeter (which lacks a capacitance-checking function) on the leads to even look for a charge, simply because of them lacking that cap-checking feature. Sure enough, I put that Fluke 87 on there and it shows "OL", the same as it does when you touch the leads to each other. Flipped it over to resistance, and sure enough, it was shorted.

Concerning the techs, I only ever saw either of them do an amperage check, but I was not there every second that either was into the condenser.

My (admittedly poor) understanding is that, if the capacitor has been shot for some time, that it would contribute to accelerated wear of the compressor. I'm wondering if that's why the last one bought it, and if this compressor is getting overworked because of it as well.


----------



## yuri

Capacitors can slowly die and they should be replaced once they lose 5% of their rated value. Ie: 50 mfd cap is good down to 47.5 mfd. They can also suddenly open up which I think has now happened. I assume you discharged it B4 testing it and that was the last straw for it. It will overheat the compressor and that contributed to the old one's demise along with normal wear and tear. May not have shown up on the techs amp readings if it was under the FLA at the time. Lots of parts changers out there.


----------



## hvaclover

yuri said:


> Capacitors can slowly die and they should be replaced once they lose 5% of their rated value. Ie: 50 mfd cap is good down to 47.5 mfd. They can also suddenly open up which I think has now happened. I assume you discharged it B4 testing it and that was the last straw for it. It will overheat the compressor and that contributed to the old one's demise along with normal wear and tear. May not have shown up on the techs amp readings if it was under the FLA at the time. Lots of parts changers out there.


Is discharging run caps a Canadian practice? I Use my meter on caps up 50mfd with no problem. Start caps start at about 100 mfd and those in all cases I have seen have bleed resistors.

No, Yuri, no disrespect to you but i just ain't buying. I can post counter arguments to everything you said but I respect and and consider you a guy of good character so i will not drag this out any further.

The floor is yours Yuri.


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## yuri

I was taught to discharge them to protect my meter and not touch the bare terminals with my fingers. Would hate to find out the hard way that was wrong. Apparently some small amperage of .00xx under the right conditions can kill a person.I guess our poster needs to post a copy of his compressor changeout.


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## hvaclover

I agree.

And with out being pissy about it the OP was very chatty, acting almost like an HVAC Groupie.

Two techs and a new comp? I don't know many folks who would go to the trouble to post his ac repair experience. This thread has been like watching a reality show.


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## yuri

I enjoy the challenge of "reading between the lines" of a problem description. A skill I have carefully honed over the years. Trying to teach that to my junior techs. CAREFULLY listening to a customers description of a intermittent problem can save LOTS of misery and unnecessary parts changing/aggravation.


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## nap

> Sure enough, I put that Fluke 87 on there and it shows "OL", the same as it does when you touch the leads to each other. Flipped it over to resistance, and sure enough, it was shorted.


every meter I have used that could actually check a cap will read OL for a period of time. It has to charge the cap before it can determine it's capacity. The larger the cap, the longer it takes to charge and check.


to checking with a ohmmeter and getting a "short".: If you checked terminal to terminal, you should initially read very low resistance and then it will increase as the cap charges eventually reading as a completely open circuit.

If you did a quick tag of the terminals, your readings are meaningless.



as to you guys tagging a cap with your fingers; why would anybody do this? Whether it has enough energy to actually cause harm or just enough to hurt, it is always a good idea to not shock yourself intentionally. I know you guys did not say you did. It was just the conversation.

to the resistor on the cap: NEC requires a cap be self discharged to less than a 50 volt charge within 1 minute after disco of the power. The resistor is the means to do this.

So, if the self discharging method is operating correctly, a cap may bite you but it should not kill a healthy person after setting for at least 1 minute.


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## Emfuser

nap said:


> every meter I have used that could actually check a cap will read OL for a period of time. It has to charge the cap before it can determine it's capacity. The larger the cap, the longer it takes to charge and check.
> 
> to checking with a ohmmeter and getting a "short".: If you checked terminal to terminal, you should initially read very low resistance and then it will increase as the cap charges eventually reading as a completely open circuit.
> 
> If you did a quick tag of the terminals, your readings are meaningless.


You are correct. Once I had the replacement in place, I brought the old one in to my (air conditioned :whistling2 bench, let it sit overnight, set my cruddy old multimeter on it via some gator clips and it started charging the cap when I put it to resistance and just let it sit. Whoops...



nap said:


> as to you guys tagging a cap with your fingers; why would anybody do this? Whether it has enough energy to actually cause harm or just enough to hurt, it is always a good idea to not shock yourself intentionally. I know you guys did not say you did. It was just the conversation.
> 
> to the resistor on the cap: NEC requires a cap be self discharged to less than a 50 volt charge within 1 minute after disco of the power. The resistor is the means to do this.
> 
> So, if the self discharging method is operating correctly, a cap may bite you but it should not kill a healthy person after setting for at least 1 minute.



Yeah, even I knew to discharge the capacitors before messing with them. One thing that struck me as strange is that there wasn't even the slightest spark or pop when I shorted each side. You couldn't pay me to discharge capacitors with my own body.

Regardless, I put in a new cap and also put in a new contactor since my old one was looking kind of ragged. The AC _seems_ to be blowing colder now, but for me, the real test will be when it rains.

Thanks for the help, everyone. I assure you, as strange as my predicament is, that this isn't some elaborate joke. I'm not sure what would be funny about me being near $900 lighter in the wallet between a new compressor, a few tech visits, and some parts.


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## nancics

I have this exact same problem!!! You never came back........ In the end did the new capacitor fix the problem for it quitting in the rain?


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## Emfuser

nancics said:


> I have this exact same problem!!! You never came back........ In the end did the new capacitor fix the problem for it quitting in the rain?


No, it turned out the compressor was shot. Once it was replaced everything was fine and the system has worked normally for the past five years. I think the behavior with the rain was because the rain would sharply increase the humidity in the air, which means more work for the system to pull it out of the air. That compressor was hanging on enough to cool air with lower humidity, but just couldn't handle the saturated air you get around here with summer rainfall. Eventually the system completely gave up the ghost and that's when I got the new compressor.


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## nancics

....I think the compressor was just replaced last year. Wonder if it would still be under warranty. The unit was new in 2009 and seems to have problems ever since. Once had low freon also. And the issue is I rent. I turned of Unit on Wednesday night when I arrived home at 7pm to 82 in house. So the landlord had a tech come out on Thursday morning after I had the unit off for over 12 hrs.....so after he turned on and checked everything it appeared nothing was wrong when he checked everything. But it took almost 24 hrs to finally get from 82 to 72 by Friday morning. So then it worked from Friday until Sunday.....but then it rained Sunday morning.....i left house for several hours.....by afternoon when I got back it was 79 then 82. So when tech told landlord all was ok on Thursday, it looks like I am crazy when I call back on Monday to tell them it is not working and it seems to be the rain. It is clear that the air blowing out of fan it not hot. And a cement slab the unit is on is soaking wet. Looking at two other units near me the cement is dry and hot air blowing out of fan. My boyfriend had this same issue but not with rain just not hot air blowing out of fan and turned out it was capacitor first and then the next year low freon......but not compressor. But for me I know it has to do with it raining for sure......I know I am not crazy!!!


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## Emfuser

Since you're renting I would be all over the landlord to get that HVAC tech back ASAP. Something on that system is wearing out. As others here have noted, it would be best to keep note of when the system seems to have problems, what sort of problems, etc so you can talk directly with the service guys instead of relaying details through the landlord.


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## Dmetzger

Emfuser, can you give me details to tell the tech. My unit is doing the same thing here in Florida. Works like a champ, nice and cold, soon as we get a rain storm, blows warm air. We had a tech out here couple days ago, he said he installed a small hard start, I have no clue what that is. It was working that day, but it rained and has stopped. I usually keep the setting above 72. Also like your situation, after these spells, I would cut it off for maybe 12 hours, but this last time it didnt go back to blowing cold air.


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## CatePhl

Emfuser said:


> I have a problem that I would like some additional help on.
> 
> My AC works fine when it is dry out. I've had a tech out here just two days ago to confirm that my coolant levels are good, the compressor works fine and gives me appropriate pressures, power draw is within spec, I'm not icing up the evaporator, and I'm getting a normal air temperature differential across the evaporator. In other words, the system works.
> 
> However when it rains, the system stops cooling. I get warm air out of the register and the compressor unit outside stops rejecting heat (it's just blowing air through the fan, but the air is not appreciably warmer, as it should be) while the fan continues to run. Usually it takes half a day or more of letting the system sit idle after rain stops before the system will blow cold air again. On more than one occasion, the system has gotten to this state and continued to run, only to eventually trip a breaker at the air handler.
> 
> I suspect this is some sort of electrical problem, but I need more information or to hear from someone who knows more about this stuff.


Hi: I am having the same problem with my compressor, but it is brand new, installed in April. Moreover, it doesn't do it with every rain storm, but when it DOES do it, it has just rained or is raining. I've had a tech check it and can't find problem. It's driving me crazy. The whole system is new and shouldn't be doing this. I get it to restart by turning everything off, flipping the breakers, and turning it back on. One thing I was wondering about. Could higher speed on fan/blower and insufficient duct work in my house be the problem? One thing I hate about the new system is a slight whistling sound from the vents. Thanks in advance for any help/advice.


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## CatePhl

CatePhl said:


> Hi: I am having the same problem with my compressor, but it is brand new, installed in April. Moreover, it doesn't do it with every rain storm, but when it DOES do it, it has just rained or is raining. I've had a tech check it and can't find problem. It's driving me crazy. The whole system is new and shouldn't be doing this. I get it to restart by turning everything off, flipping the breakers, and turning it back on. One thing I was wondering about. Could higher speed on fan/blower and insufficient duct work in my house be the problem? One thing I hate about the new system is a slight whistling sound from the vents. Thanks in advance for any help/advice.


I should have mentioned that the compressor turns off completely and the inside blower just puts out uncooled air.


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## supers05

CatePhl said:


> I should have mentioned that the compressor turns off completely and the inside blower just puts out uncooled air.


The OP hasn't been on since 2014. You may want to start your own thread. We will need the model number of the unit outside.


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