Miller (Nordyne)#Q3RC won't start (intermittent)
Posted: Fri Oct 16, 2009 8:44 pm
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.