Heat pump blows hot air on AC mode

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  #1  
Old 05-14-05, 10:01 AM
wheeler
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Heat pump blows hot air on AC mode

I have a Carrier Tech 2000 heat pump. It cooled just fine last week, but now blows hot air on AC mode.

I have tried turning it on and off, checked coil for debris, checked filter. I also checked the thermostat with a meter and find it calling for AC. Unable to check thermostat any further. I also checked a fuse I found in the air handler where the control wiring is at - the fues is fine. Both copper lines are just barely cooler than the outside air when unit is off.

Late in the winter, I had also had a problem that outside unit would not defrost. Service technician checked and said the problem is the "three way valve is stuck", and he said it would cost $1500 to repair, but said this would not effect cooling if I got past heating season. Tech indicated that he checked the circuit and defrost sensor. After tech left, I noticed that the unit was way off level. I leveled it and soon after, the defrost mode problem seemed to go away on its own and have not done anything with the three way valve - not sure if leveling helped or not.

I have some ability to test with multimeter, but need help on what to check or what to consider as the possible problems. My initial thought was that it is a referigerant leak, but, would it throw out hot air if there is a low referigerant problem?
 
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  #2  
Old 05-14-05, 11:20 AM
Ed Imeduc's Avatar
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Wink

First you dont say if the compressor runs out side and the fan there?? If the compressor is running is the big copper line hot or cold and wet? If all is running you can be low on freon but you said you didnt see any ice or frost. Boy $15K for a reversing valve is high Id say. With the unit running you can check out and see it the reversing valve has power24V to it. Most units need power to it for cool not for heat and some need power to the valve for heat .This all can go back to the defrost board Post back with more info. Stay in samepost

ED
 
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Old 05-14-05, 12:03 PM
wheeler
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Smile You saved my AC!

I checked the large copper line - it was hot. So, based on your other sugegstion I went to check for 24 v at the 3 way valve. What I found was that the electrical connection to the valve was unplugged. Plugged it in and everything works. Thanks very much for your help.

Not sure why it cooled last week - any idea? Also, any thoughts on the defrost problem that I had before? Could leveling the unit have helped?

BTW: The quote for the replacement of the 3 way was $1500 not $15,000.

thanks again you saved me a bundle.

Dale Wheeler
 
  #4  
Old 05-14-05, 12:20 PM
Ed Imeduc's Avatar
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Wink

Just hit wrong , but $1500 is still to high. Ok Id say its in the defrost board . He pulled to power off it and it stayed in heat mode for you it has to work to go into the defrost mode for you . Think defrost and AC mode is the same with that valve They make the condenser run as an AC unit

ED
 
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Old 05-14-05, 12:33 PM
wheeler
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defrost board replacement

Thanks for the time you've givin me on this problem. I have a few questions if you have a little more time.
Is the defrost board something I can replace myself? And how could the AC have cooled last week? And could leveling have couse the first problem of the unit frosting?
Thanks Again,
Dale Wheeler
 
  #6  
Old 05-14-05, 12:41 PM
Ed Imeduc's Avatar
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Yes you can do the board draw out how all the wires go.

AC have cooled last week? And could leveling have couse the first problem of the unit frosting?
Frost???? when running in heat pump outside ???? Frost on lines can be low freon in AC?????

ED
 
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