How do I wire my programmable thermostat so my A/C will work?

Question

I have a Robertshaw 300-252 digital programmable thermostat that I installed last fall. It has worked great through the winter, but when I went to turn on my a/c it will not work. I lost the instructions and this thermostat is older so I can't find a manual online.

It came with this green fuse thing and it said if your a/c did not work, connect this between two of the connectors. I have W, RH, RC, Y, and G.

I just do not know which two to connect.

When I put it on RH and RC, the fan ran but something in my basement made scary sounds so I shut it off.

Answer 1

Your R wire is your hot wire, power in wire, your w is for the gas, the Y is your cooling contactor, and G is for your Fan. This is what you want to do, take the R wire and disconnect it and just touch it to your Y. This should kick your outside condenser on, have someone tell you if it runs. If this works then your AC will work. You will want to run your R wire Y wire G wire and W wire to where they all go if this doesnt do anything then try switching your 2 R wires. If this still doesnt work then you will have to make a jumper wire and jump your 2 R wires together and then it should work. Good Luck!