OK I have an old honeywell round mercury thermostat that is connected. Ive read all the wiring help tips on several sites. I have taken the old one off carefully and looked for terminal markings and there are none. Not so good is the fact that I have 4 wires. Red and yellow jumped together and green and black jumped together. No white wire. No markings on the old terminals for letters at all.

The furnace is an oneida royal loa, the new honeywell thermostat is heat only and has a spot for the w r y wires but that doesn't help me, I have and it is a model ct87k. The wiring instructions are great. But guess what no white wire so I'm clueless. Why do I not have a white wire.:confused: :confused: :mad:

If the furnace has R and W terminals, note the color of wires connected to them, and connect the same wires to the thermostat R and W terminals. Sounds like somebody used telephone cable to wire up the thermostat. I am sure there is an extra warm spot somewhere waiting for people that don't follow color codes.

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Originally Posted by vagabond

ok I have an old honeywell round mercury thermostat that is connected. Ive read all the wiring help tips on several sites. I have taken the old one off carefully and looked for terminal markings and there are none. not so good is the fact that I have 4 wires. red and yellow jumped together and green and black jumped together. no white wire. no markings on the old terminals for letters at all.

the furnace is an oneida royal loa, the new honeywell thermostat is heat only and has a spot for the w r y wires but that doesnt help me, I have and it is a model ct87k. the wiring instructions are great. but guess what no white wire so im clueless. why do I not have a white wire.:confused: :confused: :mad:

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Where on the furnace do I look ? Near the oil burner motor? Is it on the bottom of the furnace if you can post a linke or picture of what I need to find that would be major helpful... I'm just another chick trying to keep the heat running so any help is apprecated.

You should be able to follow the thermostat cable into the furnace. Often it connects to a circuit board inside where you change the filters. There are some good pictures in the sticky at the top of this forum.

I found the wires from the thermostat connected to two thick red wires. AGain one red wire has the red and green wires attached and the other red wire has the black and yellow attached. Do I need to follow these two redwires anywhere ?

This is in the basement right where the wires I have are spliced under the floor