REPLACE FURNACE TRANSFORMER

Connect the Red and Green secondary wires the same way the secondary wires were connected on the old transformer. It doesn't matter if the colors are different or reversed, (although I've never seen red and green used)

Please turn of the caps next time.

Next time mark them as you take them off. Makes the job a lot easier. :)

The hot 24 side of the transformer goes to the thermostat. The neutral 24 side goes to the neutral side of the gas valve.

The return wire from the thermostat connects to the + side of the gas valve.

Colors don't matter. They should but sometimes don't. You have to read the markings on the transformer and the valve.

If your system was wired with color coding in mind red = red and green = yellow. They just used a two wire cable to the thermostat, both of those wires are really red.

Colbyt

I think it was "AL" who stated:

A TRANSFORMER IS AN AC DEVICE, SO POLARITY DOESN'T MATTER!!!

oh. i got carried away. sorry.

-- When the chips are down, the buffalo is empty

Please don't shout at me. Hurts my ears.

It's close to Christmas, thus the red and green !!!

This is a whisper (below)

...',,.....:....".....!;;,'``...`...`.."..--..,,,...~...:;._..=....

I think the ones I usually get have purple and yellow wires. I'll try buying some in December

Colbyt is correct in his explanation of how the unit is wired, but- and this is VERY important- there is at the very least, a limit switch that must be in the circuit somewhere. Some break the transformer primary, some the secondary, and some also have auxillary limts/rollout switches that must be in the circuit. Your best bet would be to find the schematic for your exact furnace and wire it according to that. Good luck Larry