I have a York heat pump system and I believe my demand defrost is not working properly. When the defrost cycle is working, the air out of the registers in my house drops to around 50F. The defrost cycle runs about 7 minutes and never seems to quite remove all the ice/frost on the outside unit. I am concerned that it will not be a sufficient defrost when the temperature is really low and there is ice and snow.
My system is:
York Affinity 18 SEER YZH04811 heat pump
York modular air handler MV20DN21
15KW strip heater
Honeywell TH8320 thermostat
When the heating is working, the temperature out of my registers is between 90F and 95F.
The demand defrost board has been replaced in the last two months when we first complained that the defrost cycle did not fully remove all ice/frost or snow. After replacement the service tech forced the defrost cycle. The outside unit heated up and warm air came out of the inside registers (had a smell like the heating element had not been on for a long time- like burning dust). Now when the defrost comes on normally, as I wrote before, the temperature out of the registers is about 50F.
I suspect a wiring error at the install (over three years ago). Or a loose wire/connection. Could a jumper on the demand defrost or air handler circuit boards be wrong?
Or is it proper for 50F air to come out when the defrost is on?
Any help is appreciated.