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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a RTHL3550D1006 and i am trying to install in my

Customer Question

I have a RTHL3550D1006 and i am trying to install in my house the original thermo has two red wires connected to the RC i have another red wire connected to RH how do i connect these red wires since i have three red wires
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: I called your help line but a person from India was rude and couldn't speak english. Two days
JA: Do you plan on doing the work yourself?
Customer: Yes
JA: Anything else we should know to help you best?
Customer: No all the other wires works fine. this is a conventional thermo
Submitted: 4 months ago.
Category: HVAC
Expert:  Phil replied 4 months ago.

Hello, the Rc and Rh have a jumper between them in most cases and the Red wire from the furnace connects to only one of them, so what you describe so far is normal.

Tell me if the heating failed so you decided to replace the thermostat? if that is the case the problem would most likely be inside the furnace itself.

Tell me what color of wire connected to each terminal on the old thermostat,

Red to R

Yellow to Y

White to W

Green to G

blue to C

is standard.

we can go from there

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