Normal Hybrid Heating System Operation ???
Hi all. I was an active poster about a year ago and got lots of help in deciding what I should do about replacing my ancient oil furnace and aging A/C system.
I ended up getting a Carrier system including a 25HPA6 Heat Pump and appropriate air handler, electronic filter, humidifier, and a Carrier Oil Furnace.
I intend to come back here in a few months and provide a detailed assessment of my energy savings (substantial during cooling season) and to provide some info on my new GE Hybrid Hot Water Heater.
I do have a question for you now, however. We had a not too severe winter here in the suburbs of Washington, DC. That said, my oil consumption was quite high. I recently called my installation contractor and reported that when my thermostat called for increasing house temperature, the heat pump would only run for 15-30 minutes and then heating would be shifted to the oil furnace. After verifying that my heat pump was operating correctly based on refrigerant measurements, he is telling me that it is normal for a step change in thermostat set temperature to see the heat pump run and then shift to the oil furnace.
I did not see this happen last winter in Dec and Jan when outside temp was warm "enough." (I have the heat pump lockout set to 35 deg outside temp.)
My question is as follows. Is the following scenario proper and normal?
With neither the furnace or heat pump running, I nudged the thermostat temperature setting up ONE degree. The heat pump ran for ten minutes in Single Stage. After that ten minutes, the heat pump shifted to two stage and ran for 15 additional minutes. At that point, the indicated thermostat temperature had not increased and the heating shifted to Aux heat... given time the house would see the increased temp.
If that is normal, I don't know why I paid for the heat pump as far as heating.
I do have a call in to the owner of the installation contractor and I have called Carrier.
Please educate me as to what is normal heating operation.