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Heat pump blower by temperature

jonv
jonv Member Posts: 2
in Thermostats and Controls

I have a ducted heat pump for cooling and heating for fall/spring and have a outdoor wood boiler for heating during the colder weather. I'm looking to add a thermostat to control the blower only in the air handler to come on and off based on demand in the house to push the hot air through out the house from hot water coil. The tech that did the heat pump install wasn't sure on this and not finding much help locally.

Comments

  • Kaos
    Kaos Member Posts: 257

    Depends on the heat pump and how the controls are wired. Post what you have.

  • Big Ed_4
    Big Ed_4 Member Posts: 3,044
    edited December 22

    You need a "switch on" with temperature rise aqua stat on the return piping of the heating coil to power the fan relay …

    There was an error rendering this rich post.

  • jonv
    jonv Member Posts: 2
    20241220_144021.jpg

    Here is inside the air handler, wiring to the thermostat and outdoor unit.

    I was told to " power the g terminal to run blower only" doing that turns it on but will not shut off.

  • Kaos
    Kaos Member Posts: 257

    From the R terminal run a wire to an aqua stat on wood heat supply in series with a mechanical thermostat back to the G terminal.

    This way if the wood heat is running and the mechanical thermostat calls for heat, it will turn on the fan.

  • ratio
    ratio Member Posts: 3,803

    Depending on how the OWB is controlled, you can go fancier. Use a strap-on aquastat on the return (leaving) water pipe to turn the fan on (like @Kaos said, R to G) whenever the water is hot, and use the thermostat to control the OWB circulating pump. Depending on the thermostat, it may be able to be configured to switch to the OWB based on outdoor temp/

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