Duo Therm heat pump (AC) fan runs but shuts off

Question

Looking for any help. Our AC fan comes on but everything goes off once the compressor attempts to start (I think). I can set it on fan only and it will run all day. Setting the unit to cool will run the fan for a few minutes then everything shuts off. It will continue to cycle every few minutes the same.

Oddly we have had this issue before and it went away. We've noticed that each time it has acted up, the weather has been rainy.

For good measure, yesterday I replaced the start kit (Cap and PCTR). No change. I'm not convinced yet that the compressor is bad since it has done this before but ran fine later on a dry day. Have not put my ohm meter on it yet.

Any thoughts as to what I can look at?

ductape · Answer

Check the voltage when it attempts to start, you'll probably find a loose or faulty connection. You'll need to test at various points between the power pedestal and the a.c. to find the fault(s).

jcfontenot · Answer

Thanks for the advice... I checked the breaker panel and had good voltage.  Ampmeter showed the fan drawing 2-3 amps then dropped to zero when the unit shut down (no high draw from compressor starting). So I went up and double checked everything and re-seated some of the spade terminals - to include the one from the compressor relay.  Fired it up expecting to do more testing but it's now working.  I believe it was a bad connection at the compressor relay on the control board.  Thanks!

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Duo Therm heat pump (AC) fan runs but shuts off

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