i have the heat pump with demand defrost running in steady light rain, wet, working fine at 32 to 34F degree outside, good heat to keep indoor 71F, heard compressor each cycle about 15 to 20 minutes long, ran twice per hour, and then overnight into morining, still more light rain, temperature slowly raised to about 35F or 37F outside, and heard compressor running non-stop, like 50 minutes long. went outside, and saw there was a good amout of frost on outdoor fins and looks like not defrosting.
did the demand defrost control just terminate defrosting when outdoor temperature is greater 35F? or just a bad combination of running heat pump in light freezing rain at 35F, where demand defrost not able to hand it either.
is there a manual defrost on demand defrost system?
turn off thermostat and run garden hose to rinse the frost on coil fin?
or put on coat and run AC for a few mintues?