Calling electricians - NOMA programmable thermostat wiring?

Question

My programmable thermostat was installed last fall by my dad. The heating worked fine all winter. The AC will not work now. Breakers are ok. Connections are RC ...RH (white wire on RH with a jumper in between, W-o/b (red wire), Y (white wire), G (red wire). I also tried fan alone but it does not come on. Any ideas? I also moved the wire from RH to RC and still nothing. My next step is to call an electrician unless someone here saves me;) Can't understand why the heat works just fine.

Answer 1

where are the instructions??? Its cheaper to buy a new thermostat.

Theres an extra cut off switch outside,,did U check that??

Answer 2

From what you describe, it looks like you have 2 separate pairs of wires feeding your thermostat, with a red and a white wire in each pair. Since the heat worked and the fan ran, the fan must have been switched to Auto on the thermostat. So I think the red and white wires on RH and W are wrong. Leave the jumper between RH and RC. Switch the wires between RH and W, putting the red on RH (or RC) and the white on W. If you open the furnace, there will probably be a terminal board with the R, G, W, and Y markings. Just make sure the wires match the thermostat, color for color.

You shouldn't blow anything up. The power from your transformer would go to the R terminal, and heat would go to the W. The furnace worked because the connection basically went backwards through the thermostat. Your cooling won't work because the W and Y terminals never get voltage at the same time.

Congrats Shine. Now make sure that filter is clean and enjoy a cool summer.