New thermostat - No coil control

Gigs

Hi,

I bought a new programmable thermostat to replace my old white-rogers one.

The new thermostat said it was for heat pumps "without backup heat"... I thought "Fine I don't have any kind of backup heat"

But apparently that refers to the aux coils, which I thought every heat pump had.

I don't really care about not having "emergency heat" mode or having the coils come on when the temperature is way below the setting, but I am concerned about the defrost cycle.

Will my heat pump still defrost correctly with this thermostat? I know the blue aux heat light would come on when the defrost cycle kicked in when it was really cold outside.

hvactech126

you have to have a 2 heat 1 cool thermostat ( heat pump with backup heat) in order for everything to work properly. You purchased the wrong stat. The correct stat would have to have an emergency heat function. Heat pump should defrost fine as the HP controls the aux heat during defrost. During cold days/nights when the HP cant keep up, the system will not function properly and will never bring on aux (backup) heat.

__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Gigs

Can anyone recommend a Honeywell DIY programmable 5-2 or 5-1-1 that does heat pump with aux coils? On the honeywell site every one I click says "does not work with backup heat"...

I would think this would be the most common case! I don't understand why they'd make so many that don't work with aux coils.

beenthere

http://yourhome.honeywell.com/home/P...e/RTH7600D.htm

http://yourhome.honeywell.com/home/P...e/RTH7500D.htm

hvactech126

vision pro 8000
vision pro IAQ

__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Gigs

Thanks guys I ordered the 7500D.