Hi folks, I got a heat pump installed at my home and I'm looking to better understand when/how it switches over to backup fuel in the winter.
My unit is the LENNOX ELITE EL18XPV SERIES, which I found heating specs on here
It is installed in conjunction with a heating oil fired boiler and an aqua coil as the backup heat source.
When it was installed, I asked, and the installer indicated that the heat pump will switch over to the boiler at about 37F.
What I don't fully understand though, is that this unit was billed as a variable speed/inverter, so it seems it should be able to run at lower temperatures than 37. The website above seems to indicate it should produce 31,800 BTU/h at 17F, so can I set the "switch-over" temperature of outside to be lower to use less oil?
You might need to experiment. What sort of thermostat do you have? Ecobee lets you see one single chart which type of heat is being used and the outside and inside temperatures.
From there you can adjust what temp to skip heat pump and go straight to aux heat so that you aren't wasting time and energy without making your home any warmer. It will automatically switch over of course if no temperature increase is detected within a set amount of minutes (programmed with some sane defaults of course).
I have a dual system and part of it was replaced more recently. I found the part of it that's newer can heat effectively at lower temps. They aren't the same model or anything though.
Hey, so I have an s30 lennox thermostat. For anyone who runs into this in the future, I actually managed to find it in settings under 'heat & cool" and "balance point auxiliary heat". It seems my heat pump is intended to work at the same time as auxiliary heat when it's inside a certain temperature range, switching over to auxiliary heat entirely once it gets to the lower number