mobilehomerepair.com

Hello: I have an older Miller #Q3RC Heat Pump here in FL that very occasionally will not start in AC mode. As an example, upon returning recently here to FL after about 6 months, the house temperature inside was at 89 with the thermostat set at 80. Cycling the thermostat up & down would not start it. I then cycled the main A/C breaker off, then on again and the unit started up and has been running fine for the last 5 days straight. This heat pump has done this 2 or 3 times in the past and has always restarted each time by cycling the main A/C breaker. The next time this happens, I plan to leave it off so that proper troubleshooting can be done. I was wondering if you had any ideas in the meantime as to what might be the cause of this problem? Also, what should be checked if/when my heat pump is in this condition again ? I also have a question re: the operation of this system! Should the air handler blower continue to run for a fixed time, after the compressor cycles off, to gain that last bit of "cold" from the "A" coil ? This system (blower, fan & compressor) shuts down completely immediately after the thermostat "clicks" off. I have a newer A/C system "up North" that does run for approx. 1 min. after the compressor cycles off, but that is not a heat pump. Thanks for any information you can provide. Ray in sunny FL.

Hi Ray,

I would start by checking the breaker, then transformer, t-stat, a/c condenser contactor for voltage in and out.

Since resetting breakers cures it, breaker may be weak and going bad.


To have blower remain on for short period, it must be built into t-stat, control board or have a relay installed for that purpose.


Thanks,
Robert

Thanks for the reply, Robert. I'm just waiting now for it to happen again so I can check it. I'll post back if/when problem is found. Ray

Hi Ray,

You're very welcome, happy to help. Holler if it happens again and let me know what you found.


Thanks,
Robert