Heat Pump A/C works but heat only blows cool air

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  #1  
Old 02-01-13, 09:36 PM
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Heat Pump A/C works but heat only blows cool air

I have a Goodman 5 ton split system. It is about 4 years old. The other night I noticed it was running endlessly and the air coming out of the vents were cool to cold.
I finally decided to shut it off manually because the inside temp was only getting colder and it was obvious it would never reach the target temp of 74.
The next day I called a technician. He tested the A/C side of the system and it worked fine, but he said when the Heat system is deployed it loses all pressure on his gauges and that I would need the outside TXV replaced. I am told the manufacturer will still warranty the part but it will still cost $1500 in labor and freon which is obviously disappointing on a unit less than 5 years old.
After 24 hours I decided to try the system again. The fan and everything else kicks on normally. The compressor and fan on the outside unit seem to be running normal. I felt the larger copper tube that runs between the heat pump inside to the air handler and it was very hot to the touch. Not sure if that is normal as I have never been compelled to touch it before. Still, the air coming out is just cool at best.
Now debating whether to gamble another $75 to get a second opinion or just accept the fact that this unit is junk as we have already had to replace two capacitors and a contactor on this in 4 years.
Does anybody feel that the outside TXV could well be the reason why this unit works fine in AC mode but not in heat? Are there any other 'less expensive' possibilities that I could hope for?
 
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Old 02-02-13, 09:52 AM
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It could be the TXV, it could be that you have a return off in an unconditioned area. Measure the return and supply temps at the unit. It could be that aux heat is not kicking in (if you have it).
 
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Old 02-06-13, 04:58 PM
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I ended up having another tech examine my unit. With his temp gun he determined I had a 19 degree split between the return and supply air and said that was just about normal and wanted to leave it at that. Fortunately his assistant took my side and suggested to check the outside condensor.
After running less than ten minutes in heat mode we could already see frost building up on the outside TXV. The gauges showed the unit was 5 lbs. short on R22. (holds 18lbs. total)
Also the low side larger pipe was very hot at the air handler.164 degrees according to his gun.
Checked the air handler unit inside and saw a streak of oil running down one side of the lower coils indicating a freon leak. His recommendation is change the inner coil and recharge.
Asked specifically about the outside TXV being bad and was told, no way. Would not even be heating as much as it is if it were bad.
So now I have two conflicting diagnosis and I am more inclined to believe the second opinion. The inside coil is still under warranty but the R22 I am told is $90 / lb. That would be $450 just for 5 lbs. which I do not want to spend if that is not going to solve the real problem? Why is this refrigerant so high all of the sudden? I don't remember it being that much in previous cases.
 
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Old 02-06-13, 05:42 PM
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R22 just had another HUGE price increase due to the EPA further tightening the imports of it recently.

IR temp guns are not the way to check pipe temps. Pipe clamp thermocouples are acurate at checking pipe temps. Reading gauges do NOT show you how low on refrigerant you are. The ONLY way to know how low the system is is to top it off. Go out to the HP and take a picture of the data plate (has model and serial number on it). This will show how much R22 the unit came with and is sized for a system with a 15' line set. Oil does typically indicate a leak, however, a refrigerant leak detector would tell you for SURE that it was leaking and not an oil stain from the factory or something else.
 
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Old 02-06-13, 06:12 PM
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Thank you hvactechfw! The model plate said that it came from factory with 285 oz. which is just under 18lbs. He did not use a leak detector inside. There were also signs of rust forming on the lower coils of the air handler that he said was odd for a 4 year old unit.
If we did replace the inside coil and the system works normally, would it be safe to say that it definetely was not TXV related? That is to say, can the outside TXV work fine in some conditions but not in others or is it either a good or bad part, period.
 
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Old 02-06-13, 06:38 PM
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Txv's can be tricky.... Typically they either work or they don't. If the system is low on charge then that needs to be fixed before you can actually test the txv performance.
 
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