Ptac compressors

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Old 07-07-13, 06:11 PM
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Ptac compressors

I have an old GE PTAC unit. Last year the compressor would cool for a few minutes and then would quit. Technician came out and told me it had too much freon and he let some out. Worked fine for the rest of the summer. Turned it on today and it does this: compressor starts and cool air starts out of the grill, temp is 100 degrees, cools down to about 65 degrees in about 8 minutes and then temp begins to climb and at about 75 degrees, the compressor cuts of and blows hot air. Compressor will not restart for 30 minutes or so. Please help.
 
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Old 07-07-13, 08:40 PM
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Welcome to the forums.

I'm not real familiar with those units. Does that use a separate fan motor for condensor and another motor for the blower inside or is it one common motor for both ?

It sounds like the heat is not being removed from the condensor coil and compressor.
 
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Old 07-08-13, 08:10 AM
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I appreciate your response and thanks for your welcome. There is only one motor. Please help me understand what a single motor would have to do with the compressor stopping. The compressor stops and the blower continues to moves hot air. My real concern is the symptoms now are identical to the ones last year when the technician charged me $100.00 to remove freon.
 
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Old 07-08-13, 09:21 AM
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Older units had 2 motors - One to run the squirrel cage and one for the compressor. You have to slide the unit out to see. PJ was checking to see if the compressor was overheating from the fan not working.

Does yours have an red led light near the dip switches under the fan controls? Is it flashing?
 
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Old 07-08-13, 10:46 AM
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I don't mean to argue but if the second motor is there it would be within the compressor itself. As for the red light, I would need to remove the unit and look - don't remember seeing anything like that in the past.

Did another test this morning with these results. Turned unit on and air coming from the grill was 90 degrees (it's cool this morning) and after a few minutes and some seconds it reached 70 degrees. After 8 minutes, the compressor quit. In the past, I have turned the unit off but this time I let it continue to run. After 29 minutes and some seconds, the compressor again turned on and ran for 7 minutes and some seconds and quit. I turned the unit off and left the shop.

I did find notes affixed to the inside housing that stated the unit was installed in 1977 and the compressor was replaced in 1982. This unit was removed from a motel and I have had it about 20 plus years and I only used the heating part with the unit setting on the floor in my shop. Last summer I installed the unit in the wall and ran it for cooling after the tech removed freon and it would run.
 
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Old 07-08-13, 11:26 AM
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I'd clean it up completely, then call an epa certified technician to put gauges on it to see what it's doing. It's seen its better miles, but it might be worth having someone that knows what they are doing to recover and weigh in the charge as it should have been done in the first place.
 

Last edited by hvactechfw; 07-08-13 at 02:35 PM. Reason: You must be EPA certified to service a sealed refrigerant system.
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Old 07-08-13, 05:32 PM
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Well, I don't know what to think now. I went to the shop to make sure the exhaust fan was working. I turned the unit on and the compressor hummed for a second or so but eventually started. I went outside to check the exhaust fan and it was in fact blowing hot air.

I am not EPA certified, however, I do have gauges and I have no concern connecting the gauges and I will attempt to do that tomorrow. I will need to remove the unit from the wall to do this.

I would like to clarify something and that is; the motor has a single shaft with a squirrel cage on one end and a propeller/paddle wheel on the other end. The squirrel cage pulls room air into the unit and forces that air through the cooling coils and then out the grill as cold air. There is a partition down the center lengthwise of the unit that separates this room air and the compressor and exhaust air. On the compressor side, I must assume the paddle wheel circulates air around the compressor as well as forces the exhaust air through the hot coils out of the unit. Not sure how the propeller works but it does exhaust hot air as well. And again, I must assume if there is a motor in/on the compressor it is internal. I did not see the red light but maybe tomorrow.
 
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Old 07-08-13, 05:47 PM
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We will not give you any information on refrigerant pressures and or how to know what they might mean. If you post any of that type of information your thread will be closed. You are not authorized to even use gauges without EPA certification and we can not condone such behavior. Please read rules regarding this topic here.
 

Last edited by hvactechfw; 07-08-13 at 08:01 PM.
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Old 07-08-13, 07:47 PM
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Kevin, I apologize if I gave you the impression that I would provide gauge readings or ask opinion of those readings on this thread. That is not/was not my intent at all. My intent was to provide non technical symptoms to the forum, like I have done, and ask if this thing is worth saving or should I trash it and get another.

With all due respect, a certified technician came to my home last summer and attached his gauges to this unit and ask me if I had put freon in it and I told him "no". He further stated the unit had too much and began to remove a white foamy substance into a "red rag" that I provided to keep it off the floor. Charged me $100.00 cash for that and suggested he would come back anytime for the same price. So much for your EPs certified tech.

He was the only guy that would agree to come look. I told all the AC businesses I spoke with that I would bring it to them and everyone said no. Don't plan to ask him to return but I do need cool in my shop.
 
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Old 07-08-13, 08:07 PM
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I am sure there is a company somewhere in your area that would accept them to work on. We work on them (unfortunately) all the time. However, most if not all are for commercial clients and not regular consumers.

If the person who came to your home did as you say then he was not certified or he broke the law by venting the refrigerant.

Personally, I think that for the price you can buy a unit that will hopefully fit in the current sleeve properly that I would seriously consider replacing the unit vs. the hassle and time of trying to have it repaired.
 
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Old 07-08-13, 08:55 PM
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Kevin, I wish there was a company here that would service my unit but there is not. I have found an individual I plan to contact tomorrow to see if he might help me.

As for that technician, he did in fact come to my house/shop after 5:00 pm in a company truck with the logo on the door and the Texas license number affixed to the fenders. He removed the gauges from a tool box attached to that company truck and came into my shop. When he began to expel the freon, I questioned him about removing it into the air and I don't remember his reply but I insisted I put a "red rag" on the end of the hose to keep the fluid off my shop floor.

At this time, I must consider this request as closed. Thanks to those that responded. I appreciate your time. Clay
 
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