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rheem modulating furnace

Dave_4 Member Posts: 1,405
Tim, i will check the board number on tuesday. Looks like it needs 24v in the circuit to make the humidifier work. Thanks


  • Dave_4
    Dave_4 Member Posts: 1,405
    rheem modulating furnace

    Short ouestion on the humidifer tapping on the icf board. Spec sheet says this is a dry contact point meaning this is only a switch. Can the 24 volts be pulled off the board ?? Other 92+ furnaces i have installed the humidifier tapping was eather 24 or 115 volts.
  • Dave_4
    Dave_4 Member Posts: 1,405
    rheem modulating furnace

    Any thoughts on yhis question???
  • Keith with the unit running check

    to see if there is voltage at the contact. If not and it is an internal switching contact then it is probably rated for 120 so 24 volts would not be a problem.

    What is the make and number of the board? If I have that I can look it up and give you a better answer. Usually United Technology or Honeywell boards on those. Some I have seen also have White Rodgers controls so give me a number and I can help you out.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    Must ask Tim:

    Unless the board provides a 24VAC accessory output, why risk the possibility of causing problems by "tapping in" in an unapproved manner? Simple power supplies rarely--if ever--operate at their full VA potential during normal circumstance but unless you're utterly positive you won't be drawing squat compared its' design, why not just use another (completely isolated of course via those "dry" contacts) transformer for the humidifier? "Doorbell" transformers attached to approved enclosures are dirt cheap and highly reliable.
  • Most boards

    have dedicated terminals for EAC and Hum which are powered by 120 volts usually. All the boards used on Warm Air furnaces also have an external 40 or 50 VA external transformer feeding to the Com and 24 V terminal on the board. A parallel connection to a set of dry contacts will not cause a problem.

    What may have to happen is that Hum will feed a transformer to power the humidifier. Lets wait and see what the board number and make are then we will know what to do.

    Then again who knows it may be a board I have never heard of. Then we go to Rheem for an answer.
  • John Mills_5
    John Mills_5 Member Posts: 950
    We have

    always pulled 24V from R, through the hum terminals and on to the humidistat and solenoid with no problems.
  • Dave_4
    Dave_4 Member Posts: 1,405

    Tim, Numbers on the icf board. Rheem number 62-24174-02
    Model number of board 1137-1 One other number on board
  • John Mills is correct

    for the Rheem Model # RGFD-10-EZCM furnace the "R" and "C" terminals are capable of handling the dry contact feed to the humidifier system.

    The difference on some boards is that the HUM terminals are 120 volts this is not the case here.

    Hope that helps and thanks John for your input.
  • Dave_4
    Dave_4 Member Posts: 1,405

    Thanks too all that responded.
This discussion has been closed.