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Discussion Starter · #1 ·
I purchased the 3M Filtrete (3M-22) programmable thermostat and I'm confused on how to install it. Im pretty sure im just over thinking it.

OLD THERMO WIRES:
W | B | G | R | X | O | Y

NEW THERMO WIRE OPTIONS:
C | B | O | W | W2 | Y | Y2 | RH | RC | G | A

This is how I believe I should install:
W - W
B - C (It says that If I have both B and O, I should install B to C and O to O)
G - G
R - RH
X - ???
O - O
Y - Y

Where should the X go?

Thanks!
 

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Discussion Starter · #3 · (Edited)
Model #

Its Honeywell. There are a bunch of different sets of numbers so here they are: (i believe its the first one)

LR95329-1
T874R1889

Im thinking that the X might be the common and I may not need it. What do you think?
 

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What happened to the instruction booklet that came with the new thermostat? If you have not checked the website for the 3m filtrete thermo, everything is pretty much right there.
 

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Discussion Starter · #5 ·
I have the book. And i've checked the site and all over other forums. The book dosent mention anything about an X wire so I posted up here. My system wires dont seem to properly match up with the new thermo. Any ideas?
 

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(R), Red conductor, hot side of transformer
(C) or (B) or (X), Blue, Black or Brown conductor, Common side of transformer. Not to be confused with (B) on heat pumps. If you have a (B) on a heat pump thermostat, your common will be (C) or (X)
(Y), Yellow conductor, 1st stage compressor contactor (cooling for ac or cooling and heating on a heat pump).
(Y2), Blue or Pink, second stage compressor contactor
(W), White conductor, 1st stage heat (gas furnace, oil furnace, electric resistance furnace (auxillary heat on a heat pump)
(W2), Pink or any unused color conductor, second stage of heat
(G), Green conductor, furnace blower fan.
(O), Orange conductor, Energize heat pump reversing valve to cool
(B), Blue or Orange, Energize heat pump reversing valve to heat (mainly older Rheem/Ruud).
(E), blue, pink, gray or tan conductor, emergency heating strips on a heat pump.
(T), Tan or Gray conductor, outdoor temperature compensator.
(L), Blue, brown, tan or gray conductor, service indicator lamp.
 

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Discussion Starter · #7 · (Edited)
Great thanks!

This is how I believe I should install:
W - W
B - It says "If you have O and B, connect O to O. WARNING: DO NOT connect B to B"
(Where do you think I should connect B to?)
G - G
R - RH
X - Tape up and not use?
O - O
Y - Y
 

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some old systems used both O and B. what kind of heat pump and furnace or air handler do you have? How old are they? Can you access the terminal strips in the equipment? This is the only true way to know what goes where and if your new stat will even work with your system. Does your old stat have a emergency heat function?
 

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Discussion Starter · #9 ·
Got it!
Thanks for your help but I got it working.

X goes to C
B Do not use
W goes to W2

The others match up to their letter.

Thanks again
 
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