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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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There are two wire hooked to the old mercury thermostat ;

Customer Question

There are two wire hooked to the old mercury thermostat ; and I need a red, yellow, green, and white . I am perplex on how to tie anything in THANX ahead of time
Submitted: 12 months ago.
Category: HVAC
Expert:  Phil replied 12 months ago.

Hello, tell me if you have forced air heating, and an electric cooling unit sitting outside or not.

I need to know how many unused wires (if any) are in the bundle of thermostat wires that go the thermostat.

We can go from there.

Customer: replied 12 months ago.
No air and just the two wires coming out of the wall to the old merc switch
Customer: replied 12 months ago.
I am stumped
Expert:  Phil replied 12 months ago.

No meed to be stumped.

An old mercury bulb thermostat with only two wires indicates a furnace installation with no AC attached.

tell me if you have forced air heating, and an electric cooling unit sitting outside or not.

We can go from there.

Customer: replied 12 months ago.
No cooling unit and there are only two wires coming out of the wall
Expert:  Phil replied 12 months ago.

Thanks, ***** ***** wires are needed for heating, they connect to an R terminal and a W terminal on any 24 volt thermostat rated for conventional heating, or both conventional heating and cooling.

Remove them from the thermostat and twist them together, if the furnace comes on, replace the thermostat... if the furnace does not come on, then our problem is inside the furnace itself.

In that case

Please attach a well focused, close up photo of the wiring diagram glued inside the service panel, the picture needs to betaken from straight on, in very good light.

You can use the paper clip- icon at the right end of the tool bar at the top of this dialog box to attach it here. Include a picture of the furnace itself with the service panels removed taken from about 8 feet away.

If there is no paper clip-icon, look for the '+attach files' link at left of your send button.

I can mark it up with trouble shooting instructions.

You will need a multi meter ($30 at a hardware store) and some experience working with appliances, let me know a lot about your skill sets in those regards.

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