Print

[Sawdust]

Hello,  Could someone that has experience with Honeywell multi-stage thermostats chime in.  I have read some posts wherein folks say they have used them to control the blowerfan on their existing HVAC system to distribute air from their add-on outdoor woodfurnace. They use one of the stages to control the blower when using the outdoor furnace. The other stages are used for HVAC Or another indoor furnace. How do you use the thermostat to control the blower with out having current, voltage,etc. leak or crossover to one of the other circuits ? Is there another component that is needed to isolate the circuits ? Thanks for any help, I know it is hot now, but oldman winter is a commin

[m21221]

I called Honeywell with that exact question and they said it can't be done.  I ended up with a separate thermostat and a relay.  I still think it could be done just don't know how.

[Mr Kool]

Hi,

I'm new to this board, but have owned a Hardy H4 since '96 and have been heating my house and garage
with it, I'm also a heat and air contractor and sell, service and install heating, cooling systems and ductwork
here in middle tenn.

The simplest way to have the wood furnace run first, when the rad is hot,
is to wire-tie a bi-metal like a lower water heater thermostat switch, on the copper line of the rad.

The YELLOW wire in the thermostat is the compressor on a heat pump, so break the yellow between the
heat pump furnace and heat pump condenser (outdoor unit) and connect one wire to a screw on the
bi-metal stat and the other wire to the other screw, now when the rad is HOT, the stat will open
the Yellow going to the heat pump, but the indoor blower will still come on heating the house,
when the rad is cold, the bi-metal will close and the heat pump will run.