I'm having an issue with a new heat pump with an in duct coil. Using the existing furnace for fan and emergency heat.

I can't call the factory until Monday. Calling for heT I have 24V between R and C, and R and O plus I have power to the fan. I can't get the heat pump to fire. Any thoughts?

Maybe this will help. Each column is a piece of equipment in the puzzle and how they are connected. Hope this view properly at your end. Thermostat is Heatpump enable

HP=Heat pump
Furn=Furnace force air
Tstat=Thermostat

Tstat Furn HP

[R]-----------[R]--------[R] Heat
[C]-----------[C]--------[C] Common
[AUX/E]-----[W]--------[R2] Emergency heat
[OB]--------------------[O] Heat/cool valve
[G]----------[G] Fan
[Y]-----------[Y]--------[Y] Cooling

Calling for heat, should O be energized and read 24 volts to C? That would be zero volts from O to R. I think OB is the same as W which is 1st stage heat.

Does it run in "cool"? If not, be sure the time out relay is OK. These things use a time delay relay (usually solid state) to prevent short cycling. Some times you have to wait a minute or two to see if it is going to go.,

Crap! Your right. It's been ages since I dealt with furnace controls. Before electronic stats. The R is or was commonly called common. It should be 24v between Orange and Blue, not red.

The furnace in question still called the R, common and W for heat. It tripped me up once already. Grrrrrr!

Thanx

Greetings Ya'll,

It looks like this got "Cleared up" back in May 22, 2017.

I'm curious as to how it turned out, & also why a "Duct Coil" was used, instead of an "A" Coil in the Plenum.