AC Not Cooling Enough


  #1  
Old 06-09-11, 05:49 AM
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AC Not Cooling Enough

Hi, we just started up our Keeprite AC for the summer but it doesn't seem to be working properly. For starters, when we flip the switch on the thermostat to "COOL" it takes a few minutes for it to start up. When we flip it to "OFF" it takes a few minutes for it to turn off.

When it's running, I can feel cool air coming out of the vents, but it doesn't seem cool enough. The AC is constantly running but the temperature is not going down. I changed the filter and from what I have read I should clean the evaporator coil. This is where it is located:



What would be the best way to open it up and get at the coil to clean it?

Anything else it could be that is causing these problems?
 
  #2  
Old 06-09-11, 06:19 AM
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Sounds like the system may have a timed on/off system?

What SEER is the system?
If U know the SEER there are ways to check the air-temp coming off the condenser.

Get a cheap humidity gauge at a local hardware store, as U need to know the indoor humidity.

Take all the indoor & outdoor temps U can & post them.

I'd let an H-VAC Tech check & clean, if need be, the indoor coil.

Shut power off & check the blower wheel blades for lint build-up...
 
  #3  
Old 06-22-11, 06:06 PM
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Thanks for the tips. I believe it's a 13 SEER but I'm not sure where to check to confirm it.

I checked the temperature a few times and it's usually around the same inside and outside, or it might be 1 or 2 degrees cooler inside. For example, it was about 26.5 C (about 80 F) outside so I set the thermostat to 25 C (77 F) because I wanted to see if it would cool a little bit and I didn't want to overload it. The AC turned on so I put a basic thermometer by the vent to check the temperature coming out. It was about 21 C (around 70 F) but the temperature inside never got below 25.5 C (around 70 F) and the AC constantly stayed running.

I'm wondering if the thermostat is the problem because whenever I do something, like turn the AC on or off, it takes a few minutes for something to happen.

I took out the blower to clean it. The fan is now clean but there was quite a bit of dust on the motor. I vacuumed most of it but there is still some that is stuck on and it is right in there. I took some pictures that hopefully shows it:





How can I thoroughly clean it? Would a can of compressed air work?
 
  #4  
Old 06-22-11, 06:19 PM
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Are you sure the outdoor unit is running? If it is then you need to have a pro check the charge to solve the not cooling problem. Some thermostats have a built in delay to turn on to protect the compressor from short cycling. Also some hold the blower on for say 90 seconds after a call for cooling So your stat may be functioning properly.
 
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Old 06-23-11, 05:48 AM
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Thanks for the advice and info on the thermostat. It looks like the outdoor unit is running and the air coming out the vents is pretty cool.

I want to try cleaning off the motor and see if that solves the problem. Would compressed air do a good job cleaning it thoroughly or should I use something else?

If this doesn't solve the problem, I will call in somebody to check it out. It's a little frustrating though as I have only had this unit for a few years.
 
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Old 06-23-11, 05:57 AM
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7 (77-70) degree temp split is too small. the motor is not your problem. As mentioned already, Call a AC tech to check you freon charge.
 
  #7  
Old 07-07-11, 08:54 PM
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Thanks for the all of the advice. I called in a AC Tech to check it out. First he checked the refrigerant and said it seemed to be fine. Then he checked the temperature split and said it was too small.

He noticed that the TXV bulb was mounted inside the plenum by the coil, so he moved it so that it is mounted outside the plenum. He said it would work better this way.

After the AC was running for a little bit, he checked the refrigerant again and said it is a little low. He recharged the system and also added a sealant product (I think it was called Super Seal) that would seal any possible tiny leaks.

It seems to be running fine now. I just wanted to confirm that everything sounds correct, and also I had a question about cycle times. The house is about 1950 sq. ft. and it's a 2 ton AC. What are typical run times? I haven't timed it but right now it seems like it runs for about 10 mins. and then it's off for about 10 mins.
 
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Old 07-07-11, 11:36 PM
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Not cold enough...

Well, a house that is around 2000 sq feet should have a unit larger than 2 tons unless you live in Fairbanks AL. Second why would you move the bulb of the expansion valve off the coil. It is there to sense the temperature of the EVAPORATOR COIL not the air temp of where it is now. There is an expansion valve that meters the anount of freon or flow through the system which affects heat transfer of the coils inside and out. Basically it keeps the evaporator at the correct temperature for maximum efficency no matter the load.
The proper way to fix your system is to put the bulb back where it belongs. Second find the leak in your system, would look at all the fittings first. You said that he used Super Seal to fix future leaks. What about the one you had? Did he find it and repair it or just add a can of Super Seal. Super Seal is a trade name to a product meant to seal leaks in automotive air conditioner systems. The best and proper way to repair a leak in any system is to find it and fix it. In a home system you have to braze it with a torch and silver solder or silfloss. To fin a leak you can use a soap and water solution for larger leaks and a halogen leak detector for smaller ones. Freon R22 does not wear out or needs to be changed like antifreez as some people believe. If your system does not have a leak it will last as long as the system itself. Under normal conditions you can easiallly expect to get a 15 degree temp split (temp between inside and out) and if the unit is running at peak 20 degrees. Example is if it is 90 degrees outside you can espect to get the inside down 15 degrees without too much trouble which would be 75 degrees. Most people set the thermostat to 78 degrees. There are other factors such as clean filter, attic temp (attic fan working), tight connections on ductwork, clean condenser coil on outside unit, and finally energy efficent doors and windows. The lower you set the thermostat the more it will run which may be the reason for the 50/50 runtime. Hope this clears up some items.
You say 10 minutes on and 10 off that is half the time. At what temp outside and what temp is thermostat set at. Ideally if the unit is sized right you should have 1/3 run time. 1/3 on and 2/3 off. More info would be nice like your location, temps like I said earlier. Do you have attic fan and is it working? Let us know....

Edit: I see you are in Ontario...ok you should be getting a good 15 degrees on a unit where you are with no problem. With the fact he just shot it with sealer you need to keep an eye on it and check it out before the service call warranty runs out. Another thing about sealer it takes a certain anount per size of system and the service ports where the refrigerant is put in will clog up and leak from sealant also. Like I said I'm glad it is working, just keep an eye on it.
 

Last edited by martymartin; 07-07-11 at 11:42 PM. Reason: Duh moment saw your location now...LOL!
  #9  
Old 07-07-11, 11:45 PM
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Well, a house that is around 2000 sq feet should have a unit larger than 2 tons unless you live in Fairbanks AL. Second why would you move the bulb of the expansion valve off the coil. It is there to sense the temperature of the EVAPORATOR COIL not the air temp of where it is now. There is an expansion valve that meters the anount of freon or flow through the system which affects heat transfer of the coils inside and out. Basically it keeps the evaporator at the correct temperature for maximum efficency no matter the load.
The proper way to fix your system is to put the bulb back where it belongs. Second find the leak in your system, would look at all the fittings first. You said that he used Super Seal to fix future leaks. What about the one you had? Did he find it and repair it or just add a can of Super Seal. Super Seal is a trade name to a product meant to seal leaks in automotive air conditioner systems. The best and proper way to repair a leak in any system is to find it and fix it. In a home system you have to braze it with a torch and silver solder or silfloss. To fin a leak you can use a soap and water solution for larger leaks and a halogen leak detector for smaller ones. Freon R22 does not wear out or needs to be changed like antifreez as some people believe. If your system does not have a leak it will last as long as the system itself. Under normal conditions you can easiallly expect to get a 15 degree temp split (temp between inside and out) and if the unit is running at peak 20 degrees. Example is if it is 90 degrees outside you can espect to get the inside down 15 degrees without too much trouble which would be 75 degrees. Most people set the thermostat to 78 degrees. There are other factors such as clean filter, attic temp (attic fan working), tight connections on ductwork, clean condenser coil on outside unit, and finally energy efficent doors and windows. The lower you set the thermostat the more it will run which may be the reason for the 50/50 runtime. Hope this clears up some items.
You say 10 minutes on and 10 off that is half the time. At what temp outside and what temp is thermostat set at. Ideally if the unit is sized right you should have 1/3 run time. 1/3 on and 2/3 off. More info would be nice like your location, temps like I said earlier. Do you have attic fan and is it working? Let us know....
 
  #10  
Old 07-08-11, 04:31 AM
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never should have let him use a sealant!
 
 

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