Hello,
Replaced my thermostat in the summer, everything worked good,switched the new thermostat to heat for the first time, now neither the A/C or heat work? Any Ideas?


Andy

You may have got a wire wrong when wiring your thermostat and ended up with a direct short on the heat side. Newer units will have a automotive fuse on the control board to protect the board and transformer( 3 or 5 amp fuse) if you don't have a low voltage fuse you will need to check the transformer. You need to check your breakers first to make sure one is not thrown. If you have power going to the unit you need to find the low voltage short before you start replacing parts.