I have the old mercury thermostat, it only has 2 wires, the new furnance has 8 wires (2red, 2blue, 2white, & 2Green) connecting all except the blue wires cause my furnace 2 constantly stay on, how do i wire it 2 work with the thermostat?
Two wire hookup on the old thermostat tells me that it was set up for heating only. You will most likely need a modern thermostat. But in the meantime try this with the old one. The two red wires on the furnace are probably Rh & Rc. If so these can be put "together" on the R terminal on the old stat. The two W's on the new furnace are probably W1 &v W2 This is for first and second stage heat. You can put the two "together" on the W terminal on the old stat. Do not hook up the greens (blower fan wires). Do not hook up the blue wires (They would go to the Y terminal on a modern stat for airconditioning.
Who ever sold you the furnace should have offered you a new thermostat.
Good luck....
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