Eric L asked:

I have an old heat pump w/ auxilary heat with 5 wires, Y, G, O, R, B. In the spring I bought a new digital tstat which ran the A/C fine all summer, now fall is here and the heat wouldn’t come on. Found out is was incompatible with a heat pump. Got new tstat which has E, Aux, Y, G, O, L, R, B, and C. I’ve got it wire like this now after some trial and error:

Unit - Tstat
Y - Y
G - G
R - R
B - Aux
O - B
Jumper from aux to E on the tstat

Problem now is with fan on auto, when I move the selector switch to heat the heat pump comes on and runs no matter what the set temp is. The unit is heating fine and the aux is kicking in when the tstat calls for it depending on the set and current temp, the auto control function is just not working.

Any suggestions would be greatly appreciated. I have a feeling a wiring correction would fix it.

Thanks!

Question posted courtesy of: Eric

One Response to “Wiring 5-wire heat pump w/ auxilary heat to digital tstat?”

1. Mike W on April 11th, 2008 5:57 pm

   The real answer just trying out different connections is likely to cause damage get wiring diagram for both units and wire it up correctly.