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Can use some help on this one...

WillM
WillM Member Posts: 3
I just put an outside thermostat on my new boiler to help save on gas. Realized the comfort aire air handler ahg30-0a won’t run the fan. Guessing there’s a thermostat inside of the air handler that requires the water temperature to be above a certain degree in order for the fan to turn on. Is there a way to lower the temperature setting?

Comments

  • Big Ed_4
    Big Ed_4 Member Posts: 2,762
    Depends on the aquastat installed .. In the attic on the return from the heating coil the aqustat that turns on the fan would be installed . If it's a plain preset clip on you would have to be replace to an adjustable or lower set point model . An reverse or "B' strap on aquastat with adjustments would be my choice . If one is already installed , just lower the set point. ...
    I have enough experience to know , that I dont know it all
    Solid_Fuel_Man
  • WillM
    WillM Member Posts: 3
    So I would need to buy an aquastat and wire it into the air handler In order for the fan to run at lower water temperatures (140°)?
  • Big Ed_4
    Big Ed_4 Member Posts: 2,762
    I am sure you have one , we are not sure if the one installed is adjustable .. if it is , lower it down , if not replace either to a lower set point model or a adjustable model...
    I have enough experience to know , that I dont know it all
    Solid_Fuel_Man
  • There doesn't seem to be an aquastat on board. The fan is controlled by a "Blower Time Delay", adjustable from 30-45 seconds.

    https://s3.amazonaws.com/s3.supplyhouse.com/product_files/brochure1.pdf

    It may or may not be the culprit and you would need a voltmeter to figure it out.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • WillM
    WillM Member Posts: 3
    So the AC works with the fan when called but the heat does not so I don’t think it’s the time delay
  • SuperTech
    SuperTech Member Posts: 2,139
    WillM said:
    So the AC works with the fan when called but the heat does not so I don’t think it’s the time delay
    The fan usually has a different relay for the fan to be operated in cooling. Typically it is a different fan speed than used on heating.  The cooling fan relay doesn't use a time delay.  The heating relay has a time delay to allow the hydro air coil to heat up.

    If you have a thermostat with a swich on the inside for electric or gas/oil heat you can switch it to electric and the thermostat will energize the cooling fan relay when it calls for heat.
  • JUGHNE
    JUGHNE Member Posts: 11,042
    You may find that with lower boiler water temp that the air may feel too cool for comfort.
    And if you run the fan at the higher AC speed it may be cooler yet.

  • Big Ed_4
    Big Ed_4 Member Posts: 2,762
    If the fan came on before installing the outdoor reset but now will not turn on with the lower water temperature .It would be a good guess a temperature sensor switch (aqua stat) was controlling the fan .. Look on the return pipe from the heating coil , usually install by the air handler .. What type do you have ?
    I have enough experience to know , that I dont know it all
    Alan (California Radiant) Forbes