AC barely able to cool house to below 80F - http://www.hvacmechanic.com/ Forums
Original message
| Fla Thomas
 |  "AC barely able to cool house to below 80F"
, posted Sun 6 Jun 22:22  
I'm not an HVAC mechanic, but hopefully I can learn a little bit more about my AC unit, and try to determine what is wrong. Our house has a Janitrol GMP075-3 HVAC unit, and a Ruud Achiever 9 Condenser (Model UAFD-031JAS). According to the specs on the Condenser unit, it uses R22 (Freon) coolant, and a design pressure of 150-300 PSIG. I'm hoping these specs help identify the unit.
A little back history: Recently we replaced the control board in the Janitrol unit, due to the fact that a transformer on the board burned up or shorted out. After replacing the board, we discovered that the blower motor itself would not spin up. The fan would try to spin, but would give up after a few seconds, probably after the capacitor finished discharging. The motor was siezed up, and that probably caused the overload on the control board.
After replacing the blower motor (and the capacitor as a precaution), the blower in the Janitrol unit spins up, and works fine. Now our only problem is the fact that we can't seem to get the temperature in our house below 80F. After repairing the Janitrol unit, we set the AC unit to 78F, and let it run from 4PM until 8AM the next day, just to see if everything was okay. After running for about 16 hours, the temperature in the house had dropped only from 95F to 84F. We went to check for ice on the line, and sure enough, there was a golf ball sized chunk of ice on the line just before it entered the condenser unit.
We shut off the AC unit for a few hours, and the ice quickly melted in the 95F weather. Since that one time, we've checked the line going into the condenser and it has not iced up, but still, the air coming from the vents is barely cool, a little lower than room temperature. The everything seems to run as normal, but the system is struggling to keep the temperature at 80F.
In short, I'm afraid that this will be a problem with either the compressor (in the condenser?), or a freon leak. As far as I know, the air coming from the vents should be ice cold. I know that Freon is much more efficient than newer, environmentally friendly coolants.
If I call an AC repair tech out here, I'm afriad that I will not be able to afford their services. The whole reason why I ordered the blower motor and HVAC control board and replaced them myself is due to the fact that I can't afford the $150+ in labor, let alone the $128 control board and $95 blower motor, and going without AC is unrealistic here in Florida. Possible, but miserable.
Would someone please help me determine what this problem could possibly be?
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Replies:
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| xenos
Webmaster 
| "Re(1):AC barely able to cool house to below 8" , posted Sun 6 Jun 23:09
With a completely defrosted unit run it for 10 minutes and grab the line where the ice was seen. Is the line ice cold or not. If it’s not cold the unit is short of gas, of it’s ice cold you have an air flow problem.
Xenos.
The best way to escape a problem is to solve it.
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| | Fla Thomas
| "Re(2):AC barely able to cool house to below 8" , posted Mon 7 Jun 00:07
I will shut off the AC unit right now. Will the unit be completely defrosted by tomorrow morning (~8 hours)?
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| | Fla Thomas
| "Re(3):AC barely able to cool house to below 8" , posted Mon 7 Jun 08:15
I turned the AC back on this morning, and the coolant line was not ice cold. It really wasn't cold at all.
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| | xenos
Webmaster
| "Re(4):AC barely able to cool house to below 8" , posted Mon 7 Jun 19:09
It's short of refrigerant then.
Xenos.
The best way to escape a problem is to solve it.
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| | xenos
Webmaster
| "Re(3):AC barely able to cool house to below 8" , posted Mon 7 Jun 07:40
Yes, if you leave the fan on ON it will defrost fast.
Xenos.
The best way to escape a problem is to solve it.
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| backyard mech
| "Re(1):AC barely able to cool house to below 8" , posted Sun 6 Jun 22:41
The first thing I would check is to see if you have enough air flow across your indoor coil. Replace the furnace filter and then check to see if you hooked up the motor on it's highest speed for cooling when you replaced it. Usually the black wire on the motor is high speed, if it is connect it to the spade marked cool on the printed circuit board. Additionally check to see if your returns are blocked by furniture etc. If you still have problems you may have to clean the underside of the indoor coil and the blower wheel as debris will reduce air flow.
Absolute Tempcontrol
Aurora Colorado
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| | Fla Thomas
| "Re(2):AC barely able to cool house to below 8" , posted Mon 7 Jun 00:06
Well, Honestly I am not certain how to check to see how much air is flowing across the indoor coil. I honestly do not know where it is.
The filter is brand new, and was placed in there after I finished installing the blower with the new motor on it. I also made sure I had the wires correct. The motor had a color code listed on it. Black is high speed, yellow is medium high, orange was medium low, and red was low. I connected the appropriate wires to the corresponding terminals on the controller board. I am lucky enough to have a circuit diagram attached to the inside of the door to the furnace unit. On the diagram, the terminal labled "Cool" is listed as high speed.
I do have a desk right next to the intake box of the air conditioner. While it did not seem to make a difference before, I will attempt to move the desk to another area. The only reason why the desk is in the location it is now, is due to the cramped nature of this old home.
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