# Very Very Slow to Cool Down



## cpot25 (Jun 7, 2011)

So I actually kept a log tonight from 500 until 1030 on the temperature inside my apartment. During the day, I set the auto therm to 80 as it was going to be a 95 degree day in Chicago and I work from home, but had a few appointments for a few hours. I wasn't here all day, but I would imagine the AC ran the entire time I was gone and when I got home it was 80.5 in my apartment. I shut down the AC at around 2:30 to conserve energy/money and turned it on at 5:00 during the normal cycle. Here's the results:

5:00 - 83.5 inside / 88 outside
--5:30 -- 84 inside / 88 outside

6:00 - 83.5 inside / 88 outside

7:00 - 83.0 inside / 89 outside

8:00 - 82.0 inside / 87 outside

9:00 - 81.5 inside / 85 outside

10:00 81.5 inside / 84 outside

After 5 hours of continuous use, I was able to bring my AC down 3 degrees while the outside temperature dropped 4/5 degrees. Please tell me that I'm not crazy in this situation, right???


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## Doc Holliday (Mar 12, 2011)

You're system should be cycling on and off roughly every 10-12 minutes as it should easily reach desired set point in those temps, if it is the correct sized system. 

If you have a thermometer, even one you stick into a turkey, stick it into the supply vents and get the supply air temperature and do the same for the return grill. Come back with that info and we can further help you.


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## cpot25 (Jun 7, 2011)

When I checked last night, I did the test at one of the closer ones and it was high 50s and when I did one further away it was in the low 70s.

Landlord is having the HVAC guy come by tomorrow who said he probably just needs to put in some freon?! I guess we'll see if that works.


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## Doc Holliday (Mar 12, 2011)

cpot25 said:


> When I checked last night, I did the test at one of the closer ones and it was high 50s and when I did one further away it was in the low 70s.
> 
> Landlord is having the HVAC guy come by tomorrow who said he probably just needs to put in some freon?! I guess we'll see if that works.


Air doesn't get much if at all colder than high 50's on properly charged systems. Refigerant is not your problem.

I'd have the tech check for air leaks as you should not be giving up anywhere near 10 degrees let alone more than that from one register to another. You are losing air and gaining heat in the supply air before it makes it to the living space and that is your problem.

A duct (or more than one) is loose or has a hole in it or is crushed or the insulation is gone or something is wrong with the delivery of your air.


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## cpot25 (Jun 7, 2011)

Ok, thanks for your help Doc. I'll ask the tech to check that.

Thanks again for your help.


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## cpot25 (Jun 7, 2011)

Tech came by and added freon to the system and that's it. He said if it's warmer than 85 degrees outside that the AC will not turn off and will continuously run. I find this hard to believe considering my neighbor has his AC set at 74 and it turns off all the time where mine is set at 75 and it's still 81.5 in here and only dropped 1 degree since the guy added freon.

Do I have unreasonable expectations?


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## Doc Holliday (Mar 12, 2011)

Did he check for air leaks? Did you tell him that you were losing over 10 degrees from one register to another? 

A deaf dumb and blind five year old girl could come over and just "add freon." I think she just did.


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## Doc Holliday (Mar 12, 2011)

I'd check the air temps at ALL registers again.


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## cpot25 (Jun 7, 2011)

Ok, ill check them out again and let you know.


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## cpot25 (Jun 7, 2011)

Ok, so here's what I got with a digital thermometer:

Living Room (2 vents): 65.6 and 64.9
Kitchen (1 vent): 63.3
2nd Bedroom (1 vent and 1 return): Vent 63.3 / Return 80.4
Bathroom: 63.3
Master Bedroom: 63.5
Master bath: 62.6

This is a one floor apartment on the top floor of a 3-flat. Current temperature inside is 82 and current temp outside is 92.


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## gregzoll (Dec 25, 2006)

Shutting down the system after a few hours is not going to save anything. You need to set the thermostat at the desired temp, and let it run to pull the humidity out of the air. Once the humidity level is down, then the room will start cooling. Keep in mind, the system may not be sized for those kind of outside temps, and depending on the square footage, and a few other factors, it may never get down to below 74.

Start by blocking off any direct sunlight, either by using window film that reflects the sun, and allows light, and also use room fans to move air. Seal any air leaks, if windows leak really bad, use 3m window film kits to stop air flow, door sweeps, and weatherstripping around the door frame. Let the system run, if it has to run 6 hours straight to bring the temp down, so be it. My system has ran three hours straight when the temps get high, just to cool off the house a couple of degrees, due to no insulation in the walls. Once down, and stabilized, the temp stays around 72, and the system cycles like it should.

You are actually throwing money out the window shutting it down and starting back up. Best thing is, set for 78 if you feel comfortable with that temp, and leave it.


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## Doc Holliday (Mar 12, 2011)

cpot25 said:


> Ok, so here's what I got with a digital thermometer:
> 
> Living Room (2 vents): 65.6 and 64.9
> Kitchen (1 vent): 63.3
> ...


Well now the temps are much more even yet they are higher than the high 50's you said you had yesterday. That means that your system is now possibly overcharged. When you put too much refrigerant into a system you lose coil capacity as less evaporation (picking up of heat) is possible as there is too much liquid, hence superheat charging. Do you have a txv or a fixed orifice refrigerant metering device?

I don't know what to tell you any longer. I was thinking the same thing as what was posted above, close your windows with some curtains and have a heat loss analysis performed to assure that the system is the correct size for your place. And again, have all ductwork checked for air leaks/insulation problems. 


This is going to be a constant headache until you put your foot down and demand results, you do have what is known as renter's right's.

Not to mention a system should not just have freon put into it, it should never leak period, so if you have a leak and refrigerant was needed than the leak needs to be fixed but you don't have a leak, you have an idiot hvac technician and landlord.


Sorry, but this stuff drives me batty.


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## cpot25 (Jun 7, 2011)

Doc and Greg, thanks for your tips. I was home at 11am so I put the thermostat at 75 since I was going to be gone for about 7 hours or so. When I left, the temp was 82.5 with the outside temp being in the n-hood of 85-89. When I got back home at around 7pm the temperature in the apartment was 80.5 with an outside temp in the 90s. So, after 8 hours I was able to get 2 degrees relief. This obviously didn't sit well with me and I called both the HVAC guy and landlord. Haven't heard back from either.

Is it true that when it's 85 or warmer outside, that the AC shouldn't shut off and will continuously run? My fear is that this HVAC guy may have been the one that installed the unit and is afraid to tell the landlord that it's not the right one for fear of losing his business. I may independently have an HVAC guy come from one of the bigger companies just to look at the place. Is that something that's offered?? I've never had to deal with HVAC systems before so I'm new to this game.


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## Marty S. (Oct 31, 2009)

Systems are supposed to be able to maintain 75 degrees at design conditions. In my area cooling design temp is 95 and heating is -2F. Chicago gets the same weather we do but a day later.


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## cpot25 (Jun 7, 2011)

Does that mean when it's 95 outside the system should be able to maintain 75?


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## Doc Holliday (Mar 12, 2011)

cpot25 said:


> Does that mean when it's 95 outside the system should be able to maintain 75?


With ease.


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## cpot25 (Jun 7, 2011)

Very interesting. Looks like i'm going to Yelp! to look for an HVAC guy to look at the system.

I have been able to get it to 79.5 within the past hour, so another .5 degree! Almost time for the long-johns.


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## Doc Holliday (Mar 12, 2011)

cpot25 said:


> Very interesting. Looks like i'm going to Yelp! to look for an HVAC guy to look at the system.
> 
> I have been able to get it to 79.5 within the past hour, so another .5 degree! Almost time for the long-johns.


Now that's pretty funny, spot. 

I'm in Houston, Tx and we get well over 100 degree days and MOST of our systems are in attics which get into the high 130's and all systems properly sized for the space in those temps can hold the home they are designed and sized for at 60 degrees without fail and without a struggle. 

In no way should you be having this problem. A system is not designed to run all the time as that defeats energy efficiency altogether.


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## cpot25 (Jun 7, 2011)

Yup, I agree. Once my landlord gets back from vacationing in Ireland he's going to get an earful from me.

Thanks again for your help.


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## Doc Holliday (Mar 12, 2011)

Not a problem. All these guys in this particular hvac forum are aces in their trade so come on back and ask as many questions as you need to, we're here to help and more than glad to.


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## cpot25 (Jun 7, 2011)

Anyone reading this from Chicago?


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## ryanxo (Jun 7, 2011)

Man I feel your pain. My unit is the same way. Run's CONSTANTLY from 10AM to well past 11pm. I have a programmable thermostat but I can't use it because if I let the temp go up at all it won't come back down until well after the sun goes down. 

I can let my system sit on 74 all day. When I leave in the morning its 74... when I come back in the afternoon its 76+ and the AC is constantly cranking with air coming out the vents at 68-70 degrees. 

I've had 3 techs out to my house to "fix" it.
First guy came out and cleaned both my indoor and outdoor coil and checked the freon.

2nd guy was a complete jackass. All he did was check the freon and said it was ok. I told him that much before he even freaking got there. He told me that my AC was blowing such warm air out the vents because I needed more insulation in the attic. He said my 4 inches above the "unconditioned" garage was not enough. WTF does that have to do with air coming out the vents I have no idea.

3rd guy walked outside put his finger on the lines and said yep it's charged it's working right. He then said that the unit was undersized and thats why not enough air was coming out and why it was too warm. I am so friggin pissed off with AC techs its ridiculous.

It's gonna be 99 here today and I can only imagine my house is gonna be near 80. 

I feel your pain! Will be watching your thread CLOSELY to see what your issue ends up being.


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## gregzoll (Dec 25, 2006)

cpot25 said:


> Very interesting. Looks like i'm going to Yelp! to look for an HVAC guy to look at the system.
> 
> I have been able to get it to 79.5 within the past hour, so another .5 degree! Almost time for the long-johns.


Yesterday at the peak of the day, it was 93 outside, feels like of 97, thermostat was set for 72, and the unit ran for an hour, with the temp inside around 73. I have no insulation in my walls, six inches of blown in the attic, so yes a unit could run all day and if there are air leaks, or no insulation in the walls, it could never stop. I can track my run times now on mine, since I got a newer thermostat that allows that. In my case, if I bump the thermostat up to 73, it will cycle accordingly, with a 10-15 min shut off, then cycle again for aprx 15-20 min's. I adjust my thermostat set point depending on temps outside, and can sometimes find the sweet-spot.

Try setting the thermostat for 79 and see if it will cycle like it should. Also have you looked at the condition of the indoor coils to see of clogged with dust & crap. Start by going around the house and looking for culprits such as leaking windows, and block those skylights to keep it from heating up the structure. You are fighting a loosing battle. As for Yelp, be careful, because people are paid to inflate the ratings of companies. Best thing is ask a few people which company they use and get some referrals. That is the best way. My guy is a brother of my wife's co-worker, and I trust him more than some local company here in town.

To give you an idea of my stats from yesterday:

today:


-
heat_runtime:
hour: 0
minute: 0

-
cool_runtime:
hour: 3
minute: 29

}-
yesterday:


-
heat_runtime:
hour: 0
minute: 0

-
cool_runtime:
hour: 13
minute: 2

Most of the day, the system was at 72, until I changed it to 73 around 2 pm, but yes, 13 hrs is total run time from midnight to midnight. And this was for a system in downstate IL, so yes it was a hot one yesterday. At least today will be cooler.


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