# 70 degree Supply Air



## Doc Holliday (Mar 12, 2011)

Did any of the techs mention superheat or subcooling?


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## Marty S. (Oct 31, 2009)

Any chance we can talk you into buying a better test instrument? Temp guns are not accurate enough. A multimeter that comes with a K type thermocouple and that can check amps would be best. 

The AC might be working right but one of the heat elements is coming on. Getting an accurate supply dry bulb and wet bulb temp along with the same for the return and verifying which speed the blower is on we can calculate how many BTU the AC is moving,after making sure none of the elements are on of course.


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## Kapriel (May 25, 2012)

Assuming the tech is correct and the freon level is right, and also assuming the compressor and coils are in good shape and your fan speed is correct. I was wondering if your picking up additional heat from the ductwork so that most of your cooling is being wasted in losses getting to where the cold air needs to be. I'm also guessing this system has worked fine in the past and it's not your first season with it. If it is, the AC may be undersized for the area to be cooled. Is the flex duct insulated good ? Moving more or less air will not be a factor to add more freon. AC units can only take so much freon that's why we do sub cooling and superheat measurements. Do not add more freon, if the charge is correct. If someone did add more freon they may have mix the wrong type and the system will never run right until the freon charge and type is what it's supposed to be. These are all guesses If I were to see it I could tell you right away what it was. Just my 2 cents....


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## tima2381 (Feb 24, 2007)

"Temp guns" are worthless for this purpose. Something like a $15 Weber digital grill thermometer works great. Stick it up inside the grille to measure air temperature, and give it a couple of minutes to get an accurate temp. The problem with I/R point and shoot thermometers are many. For one, they measure the temperature of a circular area whose diameter increases with distance. So if you stand on your floor and point it at a ceiling register, you're measuring the temperature of the register and the surround ceiling drywall, when you want to be measuring the air temperature. If you get closer, it will be more accurate, but you're still measuring the temperature of the register, not the air coming out of it. However, the longer you keep the thing in the cold air stream, the less accurate your results will be. I can make my Fluke read 10 F low for several minutes just by cooling it down. I once saw a tech hold his I/R thermometer under a cold air register for several minutes waiting for the temperature to drop after adjusting charge, and I was just silently facepalming the whole time. Speaking of air coming out of a register, the reason you stick a real thermometer up in the grille is to eliminate mixing with room air. Finally, temps measured at return and register can be very misleading due to heat gain if the ducts run through a hot attic. For example, you might read 13 F whereas the true drop across the coil is 20 F.


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## tima2381 (Feb 24, 2007)

tima2381 said:


> Finally, temps measured at return and register can be very misleading due to heat gain if the ducts run through a hot attic. For example, you might read 13 F whereas the true drop across the coil is 20 F.


By "misleading" I mean you might suspect your system isn't working right due to low freon or whatever, when the real problem is the heat gain in the ducts causing you to lose a lot of your cooling. If that's the case, you might be able to at least partly address the problem by wrapping the ducts with more insulation. For example, going from R4.2 to R6 might save you 2-4 F depending on length of the duct and attic temperature.


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## biggles (Jan 1, 2008)

standing out at the condenser you should have a 10F rise on air into the coils and then blowing in your face should be hotter then the day.....that suction line temp is telling us your short on freon should be ice cold like a beer can..forget about more air more freon babble:laughing: have him add air to his tires if he wants to go faster:jester:...hi speed in cooling on the air handler is so you get as many passes on the air to pull the return heat and do that 20F split there.what did the 3 brainsurgeons write on the tickets after the servcie all is working splits pressure....:huh:what.are you getting any condensation water running out of the uit....


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## tima2381 (Feb 24, 2007)

biggles said:


> hi speed in cooling on the air handler is so you get as many passes on the air to pull the return heat and do that 20F split there.


Higher speed doesn't necessarily imply better performance. You need to consider the sufficiency of the return and ductwork plus determine the proper CFM/ton ratio to balance latent and sensible heat removal. My oversized system came set on High. It should have been Medium Low the whole time, two speeds lower, the next to lowest speed. The system never worked decently on High. It worked OK for a few years on Medium. It's working better still on Medium Low, which gives me about 375 CFM/ton and significantly better humidity removal. This is all with service to set the charge properly.


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## scottmcd9999 (Jun 29, 2012)

> that suction line temp is telling us your short on freon should be ice cold like a beer can..


I would agree that perhaps the system is short on refrigerant, but I wouldn't trust the "beer can" measurement. I've seen plenty of systems working perfectly that didn't have that "beer can" effect. 



> I have the copper line outside well insulated. It is cool (67 degrees) and is condensating.
> The small line is about 95 degrees though it's 93 outside so I dunno if thats right or not


If this is an R22 system, and those are accurate measurements, then you've got some serious troubles. That suction line temp translates to a vapor pressure of ~115. If the "pressures" are right, according to the tech, and you're in the 75 psi range, then you've got superheat of 40+ degrees. If you're in the 250 psi range on the high side, then you've got about 70 deg of subcooling (which is way, way, way too much).

However, it's difficult to say this for certain unless you have accurate measurements with accurate instruments. The point-and-shoot guns are NOT accurate enough to measure refrigerant line temperatures - you need a Ktype or other accurate sensor to check those. 

Ask friends and family for recommendations. When you call those companies, ask to speak to a technician, and ask that tech if they can measure superheat and subcooling. If you get that "uhhhh ... ummm sure I guess so" sort of answer, find someone else.

Good luck in your quest to find a true HVAC technician. They're becoming quite difficult to find!


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## ryanxo (Jun 7, 2011)

Doc no they never mentioned superheat or subcooling.

Marty, the blower is on high and according to the guy who helped me find the motor speed should be blowing 1200 CFM now. I'll see if i can find better test temp test equipment.

Kapriel they didn't just pump more freon in they used the gauges to make sure it was the correct level. This is my 2nd season with the AC unit. Last year was a struggle too but I thought it was due to the lack of air movement and speed. The air movement did help but not enough. All the flex duct is R6 and the 2 i replaced i replaced with R8 and the temp at those 2 vents is the same as the rest. Though I must say at night when the sun goes down the temp coming out of the vents drops down to about 60 or so.

tima I'll get a "real" thermometer rather than the temp gun haha. So much hate for temp guns on this forum! My trunk is R4.2 fiber board and the ducts are all R6 except 2 that are now R8. It does work better on high. When it was on lo it was literally just a trickle of air coming out.

Thanks biggles ... um only 1 of the techs was a tech that actually charged me. I work for the public works division of the navy so the other 2 have been ac tech friends that I work with. The air outside blowing into my face isn't hot at all. In fact yesterday when i was cutting the grass i went over there to get a refreshing breeze. That line definitely isn't ice cold. More like a beer that has been out of the cooler for a while and is sitting on a table in a puddle.

tima the humidity in my house is normally a constant 54 or so % despite being 80%+ outside so i think its removing enough humidity. Pipe outside drips like a champion!

scott I don't know what superheat and subcooling are... guess ill need to do some research on that one. It is an R22 system. Those temp measurements were done with a thermometer my ac tech friend had. 

One of my Ac tech friends is coming out monday to check the freon levels again and see if its lost any to see if there is a leak or something.

I was definitely concerned about the air coming out of the outside unit not being hot... i remember from my parents house is was very hot.


Thanks for all the inputs guys i definitely appreciate it! I will definitely post the resolution if it ever happens


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## biggles (Jan 1, 2008)

full charge should be 10F above the temp around the condenser inlet air:wink: your missing freon....another trick is to block the air out wih a garbage can cover that LL should heat up as you slide over the air coming out,,,,, then the LL will drop in temp as you allow air to discharge...if it isn't the freon the valves on the compressor are worn when residential guy charge they always brab that suction line going into the condenser...as the gas is being sucked i the LL is filling on the actual condenser 4-5 rows and the LL to the furnace is sealed 100% liquid and the suction goes ice cold in a second...


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## ryanxo (Jun 7, 2011)

OK he will be here monday afternoon with gauges and gas so we can get it at the right levels I hope. Btw i took my wireless thermometer that normally sits in my window to see how hot is outside and i threw it up in the attic. It's 125 up there! No wonder my AC is strugglin. Time to get some more fans in that piece


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## biggles (Jan 1, 2008)

if you have a basement it being down there would make a big difference on the cycles.venting some of that 125F can only help with the supply/return ducting being surrounded by it.the air handler sucks air on that return from any place it is leaking coming back thru the attic imagine 125F attic ait mixing with your spaces 70F return..double check that collar onto the back of the air handler 360 degrees around same with the supply connection going out


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## scottmcd9999 (Jun 29, 2012)

> Those temp measurements were done with a thermometer my ac tech friend had.


Then you've definitely got some refrigerant side issues, most likely bad valves in the compressor.

As others have said, on a hot summer day the air coming off that condenser should be very warm. If it's not, you're not condensing that refrigerant, which means you're not cooling.


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## beenthere (Oct 11, 2008)

Have the guy that checks it on Monday check the temp difference at the air handler. Register temp checks don't tell you if the A/C unit is working right.

Have them take SH and SC. They will also need to take the actual indoor humidity reading, and convert it to WB, or take a WB reading.


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## Kapriel (May 25, 2012)

I know there's a lot of people commenting here. From reading some of the posts and the original post. I get the feeling the area is too large for the Cooling unit being used. Too much heat gain from attic, and other places. Also in one of the posts Ryanxo he had mentioned the supply air gets down to 60 degrees or so. And has never been right in the two years he's had it. I think there's more here. Who knows what is running inside the house, TVs, oven, lights, computers,etc. It's possible this set up will never cool the load. It's not that much tonnage to start up with.
Just a tought...


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## beenthere (Oct 11, 2008)

Its one ton per 600 sq ft.


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## Kapriel (May 25, 2012)

Ok,

What's the real load ?


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## Kapriel (May 25, 2012)

I think the real load might surprise us.... Just a thought from an old timer.


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## beenthere (Oct 11, 2008)

Kapriel said:


> I think the real load might surprise us.... Just a thought from an old timer.


His insulation could be carry enough that it needs a 2.5 ton. Its always better to improve the house envelope so that the smaller unit can handle the load, instead of just putting in a larger unit. His return could be pulling in attic air.

Electric isn't 3 cents a KW anymore.


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## Kapriel (May 25, 2012)

Food for thought,

I put a 6 ton portable AC unit the size of a refrigerator in a computer room
the size was about 12' X 12' the size of say a bedroom. 
6 tons couldn't cool the load and humidity was not a problem. The building was already being cooled. The power supplies for computers put out heat like an electric heater. Anyways I could be wrong about the size thing would'nt be the first time.


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## Kapriel (May 25, 2012)

I still remember my grandmother trying to cool down her 95 degree kitchen
by leaving the refrigerator door open....... she said it helped.:whistling2:


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## beenthere (Oct 11, 2008)

Kapriel said:


> Food for thought,
> 
> I put a 6 ton portable AC unit the size of a refrigerator in a computer room
> the size was about 12' X 12' the size of say a bedroom.
> 6 tons couldn't cool the load and humidity was not a problem. The building was already being cooled. The power supplies for computers put out heat like an electric heater. Anyways I could be wrong about the size thing would'nt be the first time.


I have 12.5 tons in a smaller computer room. on days above 95, it barely handles the load.

If the OP comes back and says he's running a server or 2 from his house, then yeah, he needs a larger unit.


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## Kapriel (May 25, 2012)

It's amazing isn't it.....

I hooked up a 25 ton Voyager to a room 25' X 25' it started to cool the room but took forever to cool it just a few degrees. Condensate waste pouring out of the trap just one of those days. 

Another job I hooked up a 75 ton Intellipak to buildings ductwork. It was pouring out condensate but only added a few degees cooling.

Both units work fine in our shop I tested them before sending them out.

I cannot control the customer's infrastructure.....


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## beenthere (Oct 11, 2008)

That s the nature of commercial.


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## hvac5646 (May 1, 2011)

Didn't see anybody post anything about how close to design temp the ODT was.

Getting a lot of units struggling here cause the heat load has surpassed our local 95* design criteria.

That the OP has other service symptoms I am not disputing. But the main cause is it's just too damn hot.


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## hvac5646 (May 1, 2011)

heres a thought: Uncle runs a sprinkler on condensers to help increase capacity on at or above average design temp days.

Old refer man's trick, I am told.


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## Kapriel (May 25, 2012)

hvac5646 said:


> heres a thought: Uncle runs a sprinkler on condensers to help increase capacity on at or above average design temp days.
> 
> Old refer man's trick, I am told.


Are you serious ?


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## gregzoll (Dec 25, 2006)

Kapriel said:


> Are you serious ?


Yep. Keeps the coil cooler, thus allowing for the freon to be cooler, in turn allowing cooler air blowing across the a-coil.

No matter how hot it is outside, the air temp coming across my A-coil is always between 42-48 degrees farenheit.


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## ryanxo (Jun 7, 2011)

Wow. Thanks to all for the overwhelming responses. There are so many suggestions I don't even know where to start. Ok thats a lie I can start out by saying yea I'm an IT guy but NO i am not running a server farm in my house. The only desktop computer we have is in my room and it's not on very often and def not during the day because yes it heats up my room and my room is the hottest one no matter what. I've worked in server rooms... i know how much heat they pump out lol.

My insulation is about 6 inches thick in the attic. I have 3 gable vents. 1 of which has a fan in it. And I have an attic fan coming out of the top of the roof. Both come on when it hits 90 up there. 

The heat the past few days has been damn hot. like 98 + with heat index of 104 so thats when i reallly noticed it struggling. It would be set on 74 all day and by 6pm it was 78 in the house.

I have checked and sealed my return... it is zip tied, mesh taped and masticed, as well as aluminum taped over that. If there is any attic air being sucked in well it's ninja air and no one can stop it.

I'll check the temp at the air handler and get back with results. ugh 125 degree attic temps.... i never wanna be up there again but I guess i have no choice.

Is it ok to wrap the air handler in insulation? After taking the side panels off I noticed that it doesnt have much inside of that thing. Would that help?

I'm still concerned that the air coming out of the condensor outside isn't hot. 

I'm going out of town this week for 4th of july but as soon as I get back on Sunday I'll be back at it. AC guy can't come today so he is coming next monday when i get back. 

And as for spraying the condensor... I did that a few times hoping it would help... hell I even sprayed the roof with the water hose on Saturday to cool the attic down. Didn't really help just made some cool looking steam. Who's idea was it to put dark asphalt shingles on rooves anyway?!


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## ryanxo (Jun 7, 2011)

Oh and for other loads in the house... most we ever have running would be computer in my room, TV in living room and maybe the xbox. Rule of the house is that neither my roommate nor myself can use the dryer or the oven during the heat of the day. As far as lights... we have CFLs and have 1 23 watt bulb that stays on in our living room most of the time. I have darkening blinds too. 

As far as energy saving when it comes to power I have it all pretty much down except this whole AC issue. I guess my next step is to re-insulate the attic with spray foam and cellulose. That is waiting till winter though because I AM NOT staying up there in this heat. heat + fiberglass = death haha


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## Marty S. (Oct 31, 2009)

Ryan when you recheck those temps use the thermometer as is on supply and return then check again with a damp sock over it. A piece of cotton shoe string works in a pinch. With dry bulb and wet bulb readings on both supply and return we can tell you what the capacity is. Get outdoor dry bulb temp at the same time.
Six inches of insulation is mighty weak. Throw another layer of R20ish batts up there the next cool morning that you have time. With the room mates help you'll be out of the attic before it gets too hot. Took mine from R20ish to R 48ish and it made a lot of difference.


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## ryanxo (Jun 7, 2011)

Thanks Marty. If i threw another layer of R20 batts up there you literally wouldnt't be able to move in my attic. That's the crappy part. It almost makes it so that I have to put an inch or 2 of spray foam down first to get a nice R14 base then throw them on top.

Ill get those temps as soon as I get back. Thanks for the help


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## gregzoll (Dec 25, 2006)

Ryan, we keep a pillar fan in our living room, so that we can move some air towards the seating area. Our house is between 72-73 all of the time, but with our Plasma on, it gets warm. As for the attic, 125 is too hot. Ours gets maybe at the highest that I have seen, 110 for just about a half hour at peak, then starts cooling down by 6pm. And we even have dark shingles on our roof, but have it well ventilated, and sealed from the conditioned space.


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## ryanxo (Jun 7, 2011)

Ok so AC guy came out and hooked up the gauges and my pressure was too high apparently. Pushing 80 psi. Looked at the service manual with the outside unit and pressure supposed to be at 70 which is what it is. Other pressure was 200 which he said was good as well.


Of course today is a much cooler day.
Air coming out the vents before he got here 63.5.
Air coming out of the vents when he left 62.5.
Air temp in the plenum at air handler 58.5
Air temp going into air handler 74
Air temp in the attic 95.

At night I have had the temp at the vents be 59 degrees but during the day it goes up to 70 coming out of the vents. 

I'm going to get a wireless thermometer and put it inside the plenum to see if that temp goes up as well on a hot day. Bad part is... it's not supposed to be all that hot for the rest of the week.

He also mentioned that he expansion valve was making a weird sound that he had never heard before but that since my AC appeared to be working correctly he did not want to tear it apart.
Could that expansion valve cause any issues?


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## beenthere (Oct 11, 2008)

Yes it could. And he should have checked charge by SC on a TXV.


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## JJboy (Oct 12, 2010)

Air temp in the plenum at air handler 
Air temp going into air handler

The difference temperature between this two points should be no less the 15. Call a Pro to check SH or SC

If the temperature air coming out of the vents are way high of the air temp in the plenum at air handler you should check you ducts, attic etc....It's no a AC unit issue


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## Marty S. (Oct 31, 2009)

Two ton moves 24,000 BTU's with 20-25% of that being moisture removal. Of that 18,000 BTU left for temp drop you're losing 5184 in the supply duct alone
(4 degree temp diff between plenum and vent x 1200cfm x 1.08). Figure the return is picking up that much or more heat means the AC is only removing 7600 btu's of heat an hour from the house and the rest is lost to the duct work.


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## beenthere (Oct 11, 2008)

Marty S. said:


> Two ton moves 24,000 BTU's with 20-25% of that being moisture removal. Of that 18,000 BTU left for temp drop you're losing 5184 in the supply duct alone
> (4 degree temp diff between plenum and vent x 1200cfm x 1.08). Figure the return is picking up that much or more heat means the AC is only removing 7600 btu's of heat an hour from the house and the rest is lost to the duct work.



The return would pick up, as the temp difference to the attic is less.


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## ryanxo (Jun 7, 2011)

Thanks for the input but all i have to say is this is wack! Why the heck do I have to tell a tech what he needs to do? Shouldn't he figure this crap out!? I mean that is his job lol. If someone brings me a PC and says it's slow I don't expect them to tell me whyy.

Marty... it's just a 4 degree change because it was cloudy outside. The other day it was 70 coming out of the vent but then again maybe the temp at the air handler was different too. I have a hard time believing the temp is increasing that much in that 2 foot return run.

Guess i have to do some more recording.


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## scottmcd9999 (Jun 29, 2012)

> Why the heck do I have to tell a tech what he needs to do? Shouldn't he figure this crap out!?


Yes, he should figure this out. A true HVAC technician will understand that you cannot properly check the charge on a TXV system using pressures alone. You must use SubCooling to do this. In fact, that's pretty much HVAC 101.

Note that some units have a chart to do this, but if the tech didn't check the temp of the small copper line (the liquid line) at the outdoor unit, then there's no way he could check SC. 

Just like it can be hard to find a good computer guy, it can be equally as difficult to find a good HVAC technician. There are many "gauge monkeys" out there who have no clue how to actually troubleshoot refrigerant system issues. If you're not dealing with established, reputable companies, and are instead shopping around based solely on price, then you'll have a very difficult time finding a true technician.

If it were me, I'd just ask the guy if they will check Subcooling and Superheat. Do this on the phone, BEFORE you setup the service call. Tell them that you simply won't pay for the service if they don't check those things, and be firm about it. Many will just hang up on you - they don't really like dealing with informed consumers - but eventually you'll find one who will do their job correctly.


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## ryanxo (Jun 7, 2011)

There was a chart that I found on the service manual for the unit when he was working on it. It had the pressure curve on it based on the outdoor temp and indoor temp and the pressures he had were right on the money. 

He didn't check the temp directly just grabbed the small line to make sure it was warm. he does work for the government so i guess thats "good enough for government work" haha.


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## scottmcd9999 (Jun 29, 2012)

Sounds to me like you've still not hired an actual HVAC tech to come out and look at your system (or if you did, you contacted the wrong one, based on the wrong factors). If you continue to work with the "magnetic sign brigade", or go with the cheapest guy in town, then you'll keep getting the same results. Those are gas-n-go guys. They just want to drop a few lbs of R22 in the thing and call it a day. They don't bother to actually troubleshoot the system, since they have no reason to do so (and generally don't have the experience, tools or expertise to do so).

You're an IT guy - do your research and find a company in your area with a good reputation for technical expertise, and contact them. They'll generally be expensive, and will probably have a bit of a backlog. They may not tell you what you want to hear (unit might be over/undersized, compressor might be shot, ductwork wrong, etc etc) but at least you'd know.


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## ryanxo (Jun 7, 2011)

I don't want to hire an actual HVAC tech...hence being a member of a DIY forum


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## gregzoll (Dec 25, 2006)

ryanxo said:


> I don't want to hire an actual HVAC tech...hence being a member of a DIY forum


Things like HVAC are not meant to be DIY. Especially when it comes to check line charges, etc.. You just have to know where to draw the line between what is a DIY job, and what is not.


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## scottmcd9999 (Jun 29, 2012)

ryanxo said:


> I don't want to hire an actual HVAC tech...hence being a member of a DIY forum


Agree with gregzoll - you have obviously reached the limit of your afterhours tech's experience (or desire to help) and now have decisions to make.

You can buy gauges, thermometers, etc etc, and read up on the matter of subcooing and superheat, airflow, duct design, etc etc ... and continue in the DIY vein. You'll very likely end up with a LOT of money and time invested, and be no further ahead of the game.

Or you can hire a competent local HVAC company with the tools, knowledge and experience to diagnose your system.

As greggzoll said, you must know when it's time to draw the line. I think that time is now for you.


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## beenthere (Oct 11, 2008)

ryanxo said:


> I don't want to hire an actual HVAC tech...hence being a member of a DIY forum



Understandable. However without actual readings of the pressure and temps we can't really give you any advice to help you. Sort of a catch 22. Does that charging chart specify if its for a piston or TXV system.


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## hvac5646 (May 1, 2011)

scottmcd9999 said:


> Agree with gregzoll - you have obviously reached the limit of your afterhours tech's experience (or desire to help) and now have decisions to make.
> 
> You can buy gauges, thermometers, etc etc, and read up on the matter of subcooing and superheat, airflow, duct design, etc etc ... and continue in the DIY vein. You'll very likely end up with a LOT of money and time invested, and be no further ahead of the game.
> 
> ...


heck, let 'em dive in nose first...what's the worst that can happen:whistling2::laughing:?:laughing:


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## ryanxo (Jun 7, 2011)

beenthere said:


> Understandable. However without actual readings of the pressure and temps we can't really give you any advice to help you. Sort of a catch 22. Does that charging chart specify if its for a piston or TXV system.


I took pics of the service manual. I can't get them to resize in this forum but they are named manual1, manual2, manual3, and manual4

I just uploaded them to my site.
http://ryantwilkins.com/AC/

If you cant read them... only thing i could find that mentioned expansion valve was:
Refrigerant Control: Expansion Valve under outdoor coil

And im guessing the worst that can happen is what I'm about to do anyway... get a new one. 

If you get bored and wanna go look at pics of my ductwork and AC and give me tips they are all at that address


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## beenthere (Oct 11, 2008)

Ok, it has a charging chart for an indoor coil with a TXV. Shows how to check for proper charge. Now all you nee is someone to check it by those instructions. It also has the FCCV/piston charging chart. determine for sure which type metering device you have. And check the charge to the appropriate instructions. A piston/FCCV system charged by TXV instructions won't cool well. A TXV system charged by FCCV/piston instructions won't cool well.


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## ryanxo (Jun 7, 2011)

beenthere said:


> Ok, it has a charging chart for an indoor coil with a TXV. Shows how to check for proper charge. Now all you nee is someone to check it by those instructions. It also has the FCCV/piston charging chart. determine for sure which type metering device you have. And check the charge to the appropriate instructions. A piston/FCCV system charged by TXV instructions won't cool well. A TXV system charged by FCCV/piston instructions won't cool well.


OK i'll see what i can do. It's not super hot so the AC appears to be working correctly. I'll wait for it to get hotter than hades again so the tech can see that not all is peachy in ACLand
In the meantime I'm gonna see if i can insulate the plenum some more and I bought solar gable fan that I'm going to install.

Also have insulation tech coming friday to give me a recommendation/estimate/plan of attack. If he is cheap enough I'll just let him do it.

Is it bad to wrap the air handler in duct wrap? What about the plenum?


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## beenthere (Oct 11, 2008)

Wrapping the air handler won't harm anything. Adding insulation to the plenum is ok if its lined.

Check to see what kind of metering deice you have now, before it gets real hot outside.


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## ryanxo (Jun 7, 2011)

Where do I find this metering device? Air handler? Compressor?

I don't know if my plenum is lined or not. It's just fiberboard. Shiny outside and fiberglass inside


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## beenthere (Oct 11, 2008)

It will be in or just outside of the air handler at the coil. Bubble wrap is ok to use on duct board.


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## ryanxo (Jun 7, 2011)

I checked. There was no TXV when i looked so i grabbed the installer guide and it mentions a FCCV(flow control check valve) so that would be what i have i suppose.

I put some radiant barrier(shiny bubble wrap from Lowes) around the air handler and got the top of the plenum covered and it didn't make a difference.

The higher the outside temp goes the higher the temp the AC puts out even though the air in the house only goes up by 2 degrees or so.

I give up on the DIY. It's not worth it. I've called 2 duct work/insulation guys and 2 HVAC guys who are coming out to do estimates this week. Luckily I think I know enough from reading so much on here that they won't be able to BS me. I'm assuming the HVAC guys will say its working fine and that it's my insulation aka I'm not going to pay them a dime and the insulation guys will say ok lets put 400 inches of insulation in your attic


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## scottmcd9999 (Jun 29, 2012)

Forgive me if I'm wrong, but it looks to me as if you have a standard heat pump air handler AND some sort of evap coil installed as well. Unless the coil in the air handler has been removed, then you've got two coils in the system, which can rob your system of performance quickly. That also means that you can't really go by the service manual (unless that coil is mated to the unit), and you'll have to go by subcooling/superheat to correctly charge the unit.

If you open the top portion of that TWE air handler (where the PVC pipe goes in) do you also see a coil? I see a drain line running out of there, but of course can't see any refrigerant lines (the pictures don't show that section of the air handler).


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## ryanxo (Jun 7, 2011)

scott,

There is an A coil in the air handler but I'm pretty sure that is standard. The 2 copper lines run from the outdoor unit up into the attic and then into the air handler. The PVC pipe is just the drain line where all the condensation drains out.


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## scottmcd9999 (Jun 29, 2012)

Okay ... scratch that last one ... the pictures were just a little confusing. You do have the evap coil installed in the air/handler, and that is correct. This pictuure (http://ryantwilkins.com/AC/DSCF0576.JPG) was confusing, until I realized that it's a picture of the return duct, and needed to be rotated to be viewed correctly.

Never been a big fan of flat-panning the bottom of an airhandler to attach the return. They should have added a plenum, or a square-to-round. It's probably not worth changing at this point, but I bet if you could take temp readings on various areas of the coil, you'd find that you weren't getting good saturation of the return air across that coil. Far better to have a plenum or S2R on there which allows for some mixing of the air just before it hits that coil.


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## ryanxo (Jun 7, 2011)

scott would that make a big difference? Like the temps I am seeing now?

At night my temps coming out the air handler are 57 or 58. In the afternoon when it's hot my air right out of the air handler is 67 or 68. Could there be anything on this crazy Trane unit that changes the temperature drop or is it just purely that my attic is hot?

At this point none of the techs say anything is wrong. I guess I'll run it like it is this summer and replace the stupid thing in the winter when it's not 105 degrees


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## scottmcd9999 (Jun 29, 2012)

I'm not sure it would make a difference, and it certainly wouldn't make a 10 degree difference - it's just not right. 

Did you ever have a tech out to check subcooling and superheat? I know you used the chart, but in cases like this you'd want to be sure and check everything.

FWIW, we don't use ductboard in my area so I don't know how much heat that ductboard would pick up, but somewhere along the way your system is picking up a LOT of heat. 

My only other comment would be this: Given that your system seems to work well when the load is off the house (i.e. at night), then my guess would be that either (a) your system is undersized or has a mechanical problem or (b) you have insufficient insulation and/or ventilation in the attic. I know some don't think active roof ventilation is needed, but in my 20+ years in the field I can tell you that I would MUCH rather work in an attic with powered roof vents than in attics with passive vents. Especially given your very low roof line, active vents would be much preferred - at least in my opinion.


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## beenthere (Oct 11, 2008)

Your air handlers return being plated off like that, really restricts air flow. ixing it will give you better air flow. Also won't have as cool of an air temp leaing evap coil, but may have enough better air flow it keeps house cooler.


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## MarkS. (8 mo ago)

I would think on the insulation if you went around and felt your walls or you said you had a temp gun check your walls temperature. I understand what you're saying about the air temp but if nothing is insulated properly nothing is going to work properly. Just my opinion. I have an old home cold in winter hot in the summer and I had injection foam insulation installed and now I have no issues. 
Hey all,

I have 77 degree air going in my return and 70 degree air coming out of my vents and the temp in my house keeps going up.

My thermostat is set on 72.
My house is 1200 Sq ft, 1 story.
I have a 2 ton TRANE XR11 unit with a 2 ton American standard air handler upstairs.
Both coils are clean.
My air filter is clean.
Air handler is on HI speed and blowing plenty of air.
I have had 3 techs out to check out my AC and they all say my freon is fine and that the only issue is my house doesn't have enough insulation. I'm calling BS.

My ducts are in my attic.
It's an extended step down plenum with Flex duct running to each vent.
My ducts are sealed... trust me ive been up there a million times checking.

I have one of those temp guns and when i check temp going into the return it's 77 degrees. Coming out of the supply it is 69-70 degrees.

I have the copper line outside well insulated. It is cool (67 degrees) and is condensating.
The small line is about 95 degrees though it's 93 outside so I dunno if thats right or not.

My attic is vented with 3 gable vents, 2 of which have fans on them blowing air out and I have a roof fan as well.

I believe its supposed to be a 20 degree drop from return to supply correct?

I have done quite a bit of research and work on this hence the plethora of information. Doc Holiday is probably tired of seeing me post and I am beyond frustrated with this stupid thing.

One of my friends told me that now that my AC is blowing more air my Freon charge needs to be adjusted. Is this true?
[/QUOTE]


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## supers05 (May 23, 2015)

MarkS. said:


> ...


10 year old thread. I wonder if that's a record here.


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## Dmccul2698 (8 mo ago)

Sweet, would have been nice to find out what actions corrected his deficiencies.


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