diff between heat pump & aux lockout temperatures in dual fuel
I'm confused about the meaning of one of the lockout temperature options in my Carrier Hybrid Heat system and hoped that someone who's an expert with Carrier equipment can help. I have the Edge programmable thermidistat. There are two options that I can adjust to set the lockout temperatures for both the heat pump and the gas furnace auxillary heat. THey are:
Option 08 - Auxiliary Heat Lockout Temperature
Option 09 - Heat Pump Lockout Temperature
Either of these can be set to Off, or from 5-55F in 5 degree increments.
On my system, they are set as follows:
Option 08 = Of
Option 09 = 45
I would like to change my heat pump balance point so that the heat pump isn't used once the outside temperature drops below above 40F. I know that I just need to change Option 09 from 45 to 40 to do that. What I'm not sure about is best setting for Option 08.
As I understand it, Option 08 is set to Off by default so the system can use the furnace any time it needs to. For example, it might take a long time for the heat pump to bring the inside temperatures up 4+ degrees so it would use the gas furnace instead. It has been my observation that the system uses the aux heat a lot more than that, sometimes for as small an increase as 1 degree. I didn't expect that. Should I set Option 09 to something like 45 or 50? What would happen if I set Option 09 to 40, so that both 08 and 09 are the same?