Honeywell thermostat

troye · #1 Oct 29, 2005, 11:26 AM

I installed a Honeywell CT87A 4447 thermostat this summer. It worked fine with my air conditioning, but I am having a problem with it controlling my furnace. It will turn the furnace on and I can turn the fan on manually, but when set to auto the fan does not come on.

The thermostat has the following terminal designations: (RH, RC, G, Y, W) and I have the following colored wires: Red, Blue, Green, Yellow, White. I have connected the Red wire to RH, blue to RC, green to green, yellow to yellow, and white to white. In addition, I have jumped RC an RH.

Can you advise if I should change any connections in order to start my fan automatically? :

labman · Oct 29, 2005, 12:05 PM

The blue, if used, should be connected to B or C. With both the red and blue connected to RC, I am surprised you didn't blow a fuse or burn out the transformer. If after you remove the blue wire, the fan still doesn't work, check the limit switch that keeps it from coming on until the furnace heats up.

troye · Oct 29, 2005, 12:59 PM

seems to have worked

thanks a million



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