Wiring in line booster fan

Discussion in 'HVAC Heating & Cooling' started by cpeters, Apr 7, 2019.

  1. cpeters

    cpeters In the Trades

    Joined:
    Sep 20, 2005
    Location:
    New Jersey
    I'm putting in a booster fan and need a way to trigger it when the ac comes on. It's a carrier FX4D used only for cooling. Someone suggested a Suncoast temp sensor and plugging in to that. Couldn't I also connect into
    a taco switch relay TACO SR501 and trigger it from the 24volt thermostat. Are there relays for this purpose or
    am I overthinking this? Thanks in advance.
     
  2. Stuff

    Stuff Well-Known Member

    Joined:
    Mar 7, 2013
    Location:
    Pennsylvania
    SR501 is overkill for this. You are correct in using 24v from the thermostat. Easier is normally to tap the G and C wires at the air handler but you can get them at the thermostat if there is a C wire there. Then drive a relay such as https://www.amazon.com/Functional-Devices-Ribu1C-Relay-Enclosed/dp/B000LESCI2 . Mount the relay at the fan junction box so you only have to run low voltage wires for any distance.
     
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    You could use a vane/sail switch to trigger it on. It would be best if it controlled a relay. When the switch saw air flow, it would close, that would trigger a relay to apply power to the fan. There's more than one way to do this, and some of it would depend on where the motor was in relation to the air handler, how easy it is to run wiring, and the availability of power in the region.
     
  5. cpeters

    cpeters In the Trades

    Joined:
    Sep 20, 2005
    Location:
    New Jersey
    Thanks for the help. I ordered the relay.
     
  6. cpeters

    cpeters In the Trades

    Joined:
    Sep 20, 2005
    Location:
    New Jersey
    Thanks.
     
  7. cpeters

    cpeters In the Trades

    Joined:
    Sep 20, 2005
    Location:
    New Jersey
    FYI,
    it took a day and a half to get RIB(Relay in a Box)
    It works like a champ.

    the white/yellow to the common 24v
    the white/blue to the fan activator on thermostat(G)
    The solid yellow to the 120 line
    The solid orange to the hot side of fan.
    Fan ground to line ground
    fan neutral to line neutral.
    The solid blue and Black/white capped off

    Thanks for your help.
     
    Last edited by a moderator: Apr 13, 2019
  8. fitter30

    fitter30 Well-Known Member

    Joined:
    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    A curent sensing relay would of worked also
     
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