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  1. #1
    Join Date
    May 2008
    Location
    GTA, Ontario, Canada
    Posts
    20

    Command Aire Heat Pump Tstat Wiring

    Unit info: Command Aire m/n:SWPR611EA, s/n: J8965733, thermostat: Honeywell T874C1117. Thermostat terminals: W1 W2 G R O Y1 E X1. Terminals on the unit: R Y1 Y2 G W O B. My question is what wires from the thermostat go to which terminal on the unit? The customer has ripped apart the electrical on the unit and I get to rewire it now. Looks like we have everything in order now other than low voltage. On a call for heat the compressor contactor arche's and "chatters" fyi I changed out the contactor. Boss suspects its the low voltage wiring. Any help is greatly appreciated.

  2. #2
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,841
    I don't have the t-stat wiring diagram but I'd bet there's a loss of voltage causing the chattering. Perhaps the common wire back to the indoor unit isn't wired in or is missing entirely??? You can always prove the contactor is good by running 24-Volts directly to it, whether that's using an on-board transformer or a troubleshooter transformer from you truck. I doubt the coil is the problem but that's one good way to prove the contactor is NOT at fault.

    The only difference between Y1 at the stat and Y1 at the outdoor unit is the 4-way valve "O" at the outdoor unit shifting.

    http://customer.honeywell.com/techli...0s/69-0012.pdf

    See if this helps.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  3. #3
    Join Date
    May 2008
    Location
    GTA, Ontario, Canada
    Posts
    20
    my mistake, forgot to mention its an open loop (water from a well) heat pump system (like a geothermal). Theres no outdoor unit (condenser coil).

  4. #4
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,841
    So what? What does that change? The only addition is a contactor/relay to start the loop pump(s). Everything else is the same. A heat pump is a heat pump and the "outdoor" unit is the ground/earth coupling. You still have a HP indoors, still have an air handler (if it's water to air, you didn't say) and still have a t-stat with low voltage wiring. Where's the mystery?
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  5. #5
    Join Date
    May 2008
    Location
    GTA, Ontario, Canada
    Posts
    20
    Just looking for help from others with more experience on these systems brother, thanks for your input.

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