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Heat pump, hydronic baseboard hybrid system.

pmarinello489
pmarinello489 Member Posts: 23
in Thermostats and Controls
As the title says I recently had a carrier performance series 16seer heat pump installed and already had hydronic baseboard heat (oil burner) the installer installed it on one thermostat, as a heat pump system w/ electric coil aux heat with a relay because thermostat can't control two 24v systems. Whatever thats all fine until you want to run aux heat by itself or when you set a lockout temp and aux heat kicks on compressor kicks off air handler always runs as long as heat is running (even on boiler only) which makes the house drafty and why waste electric... Does anyone know what relays would be required and where the must be hooked up to fix this. Right now I just have thermostat reconfigured to duel fuel but that mean my boiler can never supplement my heat pump just take over, not exactly what i wanted... anyone with an answer installer pretty much left me hanging...

Thanks

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,696
    Problem is... your heat pump and your boiler are not going to play well together if both of them are running at the same time. That's why the dual fuel setting (which is correct) is the way it is. You may need a second thermostat -- one for each -- and set up one to bring the heat pump on and the other the boiler, then figure out when you want each to run... and set the heat pump to turn off its auxiliary heat.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Ironman
    Ironman Member Posts: 7,537
    Separate the "W2" and "Em Heat" terminal wiring at the thermostat. You may also have to program the stat to operate these terminals separately. Connect the boiler to run off of the "EM Heat" terminals through a 2 pole, double throw isolation relay.

    Use the "NO" contacts on the first pole to close the "TT" terminals on the boiler.

    Use the "NC" contacts on the second pole to interrupt the fan input (G) to the AHU.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    SuperTech
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,364
    What @Ironman said.

    If you have electric heat coil for emergency heat disconnect it and use the boiler for emergency heat.
  • pmarinello489
    pmarinello489 Member Posts: 23
    I have no "backup heat" in the air handler. Only the heat pump, and an oil burner with baseboard hot water heat. Right now I don't have anything hooked up to the Emergency heat but Only to AUX (which functions as both). I can understand what needs to be done I'm just finding it so confusing.

    I have a honeywell t10, so once it is wired everything should work. Thermostat is super straight forward.
  • pmarinello489
    pmarinello489 Member Posts: 23
    edited February 2020
    new question @Ironman , when you say seperate the W2 and Em Heat at the thermostat what is it that you mean. Right now I have obviously 1 wire for the AUX, which goes into the attic, into a RUb1c relay, and back down the wall pigtailed into the original "boiler thermostat cable" to the basement. What do you mean by seperate? am I bringing a new wire from the boiler, or am I pigtailing whats there, or should I call a professional! My father is an electrician with some HVAC experience, I'm just slightly confused because I didn't do the oringal wiring and there is already a relay in the attic.
    I just realized i may be having a brain fart.. but the relay is going to seperate my W2 and EM Heat.... Correct?

    Thanks
  • Ironman
    Ironman Member Posts: 7,537
    Most thermostats connect "W2" & "EM Heat" together, whether by a jumper or programming. You have to arrange the stat so that they are independent of each other.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • pmarinello489
    pmarinello489 Member Posts: 23
    edited February 2020
    my thermostat has a setting to configure them independently, I was wondering how I am PHYSICALLY getting 2 wires from the one white. So I can wire in W2 and EM Heat. I think this may be over my head only because I don't know what the hell is already going on. In concept I totally understand, doing it I'm confused lol
  • Ironman
    Ironman Member Posts: 7,537
    If your AHU doesn't have any back up heat installed, then you don't need w2.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • pmarinello489
    pmarinello489 Member Posts: 23
    Instead of starting a new thread was curious if I can disconnect AUX heat wire from outside compressor because I notice a lot of random calls for AUX from this Carrier Unit. For example I had a call for heat, AUX and air handler kicked on for maybe 45 sec. to a minute. I wouldn't care but it's def not good for my boiler. Also on a defrost who needs 2 minutes of baseboard... it's useless and not efficient. Thanks for all the help guys.

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