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I bought the CT87K Thermostat. I have a steam furnace. I…

Customer Question
I bought the...

I bought the CT87K Thermostat. I have a steam furnace. I have three wires, but I think I only need to use two. How can I find out which wire is R and which is W?

Contractor's Assistant: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?

Just rewiring.

Contractor's Assistant: Do you plan on doing the work yourself?

Yes

Contractor's Assistant: Anything else we should know to help you best?

No , power is off and old thermostat which did not work is removed.

Submitted: 11 months ago.Category: HVAC
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Answered in 3 minutes by:
10/1/2017
HVAC Technician: Rick, HVAC Supervisor replied 11 months ago
Rick
Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 24,843
Experience: 40+ yrs. experience as a licensed oil & gas technician.
Verified

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

It's usually red & white but you need to go to the boiler and check which leads are connected. How old is the boiler?

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Phil, Mechanical Engineer
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