Aux heat turns on with 2 degree delta??

GreyGoat · Feb 14, 2022

I'm in Texas. We had some pretty cold weather last week and during that, I figured out my electric strip heaters (aux/emergency heat for my heat pump system) were not working well.

I had an AC company come check it out - they found 1/2 of my strip heaters were dead. I had this replaced.
Maybe it's always been like this, but I haven't noticed it. Whenever I go to heatup more than 1 degree, my aux heat kicks on.

I've got a Honeywell TH6220D thermostat. From everything I've read, the aux heat is controlled by the thermostat and should not kick on until I have a 3 degree delta between set and actual temp.

This has happened when really cold....but also with outside temp roughly 50 degree.

So.....any thoughts?

Is there anything else that will cause the aux heat to kick on in this scenario?
Is there any way to widen this band? Everything I've read in manuals for these and from other sites indicates I can turn off the aux heat in the advanced settings, but I don't see anywhere that the delta can be adjusted.

Thanks in advance for any input folks!

user_12345a · Feb 14, 2022

It shouldn't be bringing aux heat on when it is 50 degrees unless you've manually raised the thermostat temperature, so your heat-pump may not be working properly.

Honeywell thermostats do not run off of fixed differentials - they have intelligent firmware, when the software sees the heatpump is unable to keep up on its own (temperature falling), it will start cycling on aux heat.

Reducing the aux heat cycles per hour setting should make it less readily bring on aux heat.

But get your heatpump checked before doing that.

roughneck · Feb 14, 2022

Are you resetting the set point of the unit? As in lowering/raising it?

Aux heat turns on with 2 degree delta??

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