Hi,

I called Honeywell to find out which thermostat I need for my heatpump system. I told them the current wiring on the old thermostat and was advised to buy the RTH7500 or RTH7400.

Here is how I was told to wire it:

Old to New
Y1 to Y
R to R
G to G
O to O
W1 to Aux (jumper from Aux to E)
C to C

Node setting 0170 set for #7
Node setting 0190 set for #0

However, when I was reading the instruction manual, it says if my old thermostat has Y1 or W1 (I have both) then I need to stop now and call a contractor for help. So I am confused because they didn't tell me this on the phone, they told me how to do it myself. I tried to call them back and ask why, but they are closed for the weekend.

Does anyone know why I need a contractor because of the Y1 and W1 wires?

Thanks!
Mona