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Heating, Air Conditioning, Fridge, HVAC/25 year old carrier heat pump hot pipe outside


Hello! An answer to your question:

QUESTION: bonjour, my central heat pump is not giving cool air after 3 hours, the copper pipe outside is hot hot, no frost. they changed everything fan,compressor,2 way vavle, last hope, thank you

ANSWER: Hello Ghislain, If you are taking about the larger pipe that is hot, then the reversing is not working. If you have a voltmeter I can help you test it. We will need the model# of the heat pump.

Let me know.

---------- FOLLOW-UP ----------

QUESTION: heat pump serial # 2489E26469
model # 38SQ124300

ANSWER: From the serial #, I think the unit is 25 years old. I couldn't find any wiring diagrams on the net. There is a easy test we can do. Turn power off to the furnace. Remove the stat and expose the wires. Remove the R wire, G wire and Y wire and twist them together. Turn power back on. Let me know what happens.


I PUT THE THREE WIRES TOGETHER , THE HEAT PUMP GIVES ME HEAT,80 degrees, when everything was hooked up before ,the compressor would run,but the cold air would run out after 3 hours, and the bigger piper outside was hot, NOW WITH THE HEAT ON AT 80 degrees,the small pipe is hot, and the big pipe is cold,
salut ghislain


It's good to hear back from you. Have you replaced the thermostat recently? Sounds like the reversing valve is working back wards. You can test this by setting the stat to call for cooling, then go outside and pull the plug on the rev valve. Put your meter in the plug, you should see 24V.

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Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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