I am replacing a HydroHeat thermostat that came with the HydroHeat geothermal heatpump system. It is an old manual mercury filled Tstat that has never seemed to be accurate as far as temperature etc. Anyway I bought a Honeywell Programmable RTH7500 series. It says it is compatable with heatpumps and multi stage heat systems.

Wiring it seemed simple except for one wire.

HydroHeat Honeywell
R to red R to red
O to Orange O/B to Orange
G to Green G to Green
C to blue C to blue
Y1 to Yellow Y to yellow
W2 to white Aux to White
Jumper W1 to Y1 ??????


New Tstat does not have a W1 marking on the heat pump side. It does have a W on the conventional side in the same spot as the O/B.

All the wires hook up except the jumper. I am not sure where to jump the Y1 wire to. In the instructions it says that if Y1, W1 and W2 are in use on the old thermostat (which they all three are) then to stop and call a qualified contractor.

Any help you can provide will be helpful. Thanks.

 

Jumper is not needed on the newer stats.

Add a jumper between E and Aux.

 

All right I will try the jumper from e to aux.

Thanks for quick answer.

 

Glad to help.. If something is not right, please let me know.