I have a Honeywell rth2510c and don't know where the blue wire goes. It was in c on [Archive]

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Barbara Donatel

Jun 12, 2016, 08:52 AM

The blue wire was connect to c position on my old thermostat and I don't know where to connect on my new Honeywell RTHL2501C thermostat

ma0641

Jun 12, 2016, 09:34 AM

Gas heat or heat pump? Installation manual should show you. In some installs, blue is not used. Might be for auxiliary or electric heat. Tape the end, finish install. If it runs, just push the blue back into the wall. Read pgs 22-25 of install manual.