750mv vs 12v Thermostat Question UPDATE 2
Updated 29 Nov-- Update 2--29 Nov: got it to work. Not clear on the thermostat voltage for these things whether I can use the cheaper version or what. I want it for my furnace only set-up in the R...
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Well this is embarrassing---The two wires into the back of the old thermostat are both blue! I was all wrong about pos and neg.
EDIT--- OR NOT ???
I put the meter across the old one's two blue wires at W and R common and got 13.85 volts. Switched leads and got -13.85 volts. The positive reading was with the pos lead on Terminal R common in the manual's diagram and the neg (common as marked on the meter) on W
Seems backwards? Anyway now I am sort of nervous which wire to put where on the new thermostat.
The wiring diagram on page 5 in that link does show the two blue wires to the thermostat as "Thermo + " and "Thermo" but not where they go in the thermostat.
My manual's diagram says "connect the two wires which run from the furnace to the back of the thermostat base" Doesn't say which terminals for which wire.
EDIT--- OR NOT ???
I put the meter across the old one's two blue wires at W and R common and got 13.85 volts. Switched leads and got -13.85 volts. The positive reading was with the pos lead on Terminal R common in the manual's diagram and the neg (common as marked on the meter) on W
Seems backwards? Anyway now I am sort of nervous which wire to put where on the new thermostat.
The wiring diagram on page 5 in that link does show the two blue wires to the thermostat as "Thermo + " and "Thermo" but not where they go in the thermostat.
My manual's diagram says "connect the two wires which run from the furnace to the back of the thermostat base" Doesn't say which terminals for which wire.
