
Look at the thermostat wiring photo you took. The following are wiring diagrams for common systems,
please confirm you have a C connected to your old thermostat.
Terminal Conventional System Heat Pump System
RC Power for cooling, 24V Power for cooling, 24V
RH Power for heating, 24V Power for heating, 24V
CCommon wire,24V Common wire, 24V
GFan Fan
Y1st Stage Cool 1st outdoor Stage Heat
Y2 2nd Stage Cool 2nd outdoor StageHeat
W/E 1st Stage Heat 1st Stage Auxiliary/Emergency Heat
O/B/W2 2nd Stage Heat Changeover (reversing valve)
connection for heat pump