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Flue Damper Wiring

When a flue damper fails, I always remove it from service. Why is another story.

What I'm after here is to figure out the wiring in order to jumper the end switch to get the boiler running, but it's hard for me to discern the 24 volt wires from the end switch wires. I need someone smart (like Jamie) to explain it to me.
Often wrong, never in doubt.

Comments

  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,256
    What color wires do you have on it Alan?
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • HVACNUT
    HVACNUT Member Posts: 3,904
    Most flue dampers (I know Fields controls does) have a small switch on the motor to leave the damper open. The open damper keeps the end switch closed.
    Checked around the burner compartment. There might be a molex jumper hanging somewhere.
  • What color wires do you have on it Alan?

    Orange, brown, yellow and black on Field's molex plug. On Hydrotherm boilers, this molex mates with a molex with blue, white, red and black wires.
    Often wrong, never in doubt.
    Dan Foley
  • EzzyT
    EzzyT Member Posts: 1,119
    The orange and yellow are the end switch, brown and black are the power leads for the vent damper
    Creative Solutions Plumbing & Heating LLC
    Lic #12683
    Co-Owners: Fred Drescher, Jr & Eliezer "Ezzy" Travis
    201.499.0223
    Alan (California Radiant) Forbes
  • GW
    GW Member Posts: 4,083
    I resort to ohming out the leads that close the burner circuit
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
    Zman
  • Do you mean the leads going to the ICM?
    Often wrong, never in doubt.
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,256
    edited December 2018
    Black and red are the end switch, which if you connect together the burner will run forever. Blue and white are the power to the damper motor. If you remove the damper completely, then all you need to do is connect the blue and red. This is the boiler side of the molex. That way the 24v which powered the motor and went through all the safeties/limits will power the gas valve.

    If you have a picture of the wireing diagram, I can confirm 100%.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Often wrong, never in doubt.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,796
    To me it looks like jump blue and red to run burner and disconnect black & white which looks like damper power.
    Alan (California Radiant) Forbes
  • GW
    GW Member Posts: 4,083
    Hey Alan

    black is 24 neutral
    White is 24 voltage
    Blue is the signal from the thermostat to open up.
    Red is the “end switch” that send a signal to the ignition control

    So jump blue and red and that bypasses the stack damper. Obviously you want to disable the damper and keep the power off of it if you bypass it, open of course
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
    Alan (California Radiant) Forbes
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 2,753
    edited December 2018
    Gary & Ed: OK, jumping blue and red makes sense to power the ICM which answers my question; Thanks!

    But I'm looking at the white and black terminals (1 and 2) on the lower drawing and it looks as though they are continuously powered. They connect directly to both legs of the transformer without any devices. OK, now I get it. I always thought there was an external switch (i.e. thermostat) that sent power to the damper, but there's a relay on the damper circuit board that closes and operates the damper.



    Often wrong, never in doubt.
    GWSolid_Fuel_Man
  • Steamhead
    Steamhead Member Posts: 14,407
    If it's a Field or Effikal damper, you can replace just the motor assembly- don't have to replace the whole damper or figure out how to bypass it. We stock these replacements.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • GW
    GW Member Posts: 4,083
    Yes it needs full time power because when the blue drops out, the motor still needs power to close the damper.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,256
    Blue and red need to be connected to bypass the damper, as been said. The diagram I was looking at before was different.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • GW
    GW Member Posts: 4,083
    Steamhead said:

    If it's a Field or Effikal damper, you can replace just the motor assembly- don't have to replace the whole damper or figure out how to bypass it. We stock these replacements.

    I'm not a motor expert, is Effical and Field one and the same? I'd like to get a couple of motors for the trucks
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]ilsonph.com
  • GW
    GW Member Posts: 4,083
    EzzyT said:

    The orange and yellow are the end switch, brown and black are the power leads for the vent damper

    Different motor wire colors- yet you're right



    LOL my spell check doesn't work in Paint
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Zman
    Zman Member Posts: 6,527

    When a flue damper fails, I always remove it from service. Why is another story.

    Ok,
    I have been thinking about the why.
    Do you have time for that story?
    Does the customer request it so they can start wasting more energy up the stack?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • GW
    GW Member Posts: 4,083
    @Zman it's several pound of potatoes to fix the damper, compared to the 'waste' up the chimney--- is several grapes, so it's not a big concern
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Steamhead
    Steamhead Member Posts: 14,407
    edited December 2018
    GW said:

    Steamhead said:

    If it's a Field or Effikal damper, you can replace just the motor assembly- don't have to replace the whole damper or figure out how to bypass it. We stock these replacements.

    I'm not a motor expert, is Effical and Field one and the same? I'd like to get a couple of motors for the trucks
    That's correct. Field bought out Effikal, and the motor mounting is the same. Edit: there are two part numbers: GVD-RMA- PL with the plastic base or GVD-RMA- AL with the metal base.
    GW said:

    @Zman it's several pound of potatoes to fix the damper, compared to the 'waste' up the chimney--- is several grapes, so it's not a big concern

    That depends on what sort of chimney you're hooking up to. ISTR the AFUE test uses a chimney built to current standards, so the difference was noticeable but not earth-shaking. But in a pre-World War II house, the chimney would have been designed for a coal boiler which required much more draft. Some of these chimneys could pull pets and small children up to the roof. In this case, the draft would cool the boiler down quickly, so the damper is essential for good seasonal efficiency.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Zman
    Zman Member Posts: 6,527
    I guess it depends on the setup and the owners preference. The boiler turns into a radiator as soon as it turns off. An open vent makes it a very effective radiator.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • GW
    GW Member Posts: 4,083
    Yes my comment was extremely general. Whatever is best is best

    If the chimney has excessive draft, I would think the draft hood would do most of the “work” (there’s gotta be a better word than work)
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Steamhead
    Steamhead Member Posts: 14,407
    GW said:

    Yes my comment was extremely general. Whatever is best is best



    If the chimney has excessive draft, I would think the draft hood would do most of the “work” (there’s gotta be a better word than work)

    It would, while the burner is running. When the burner shuts off is when you need the damper.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • GW
    GW Member Posts: 4,083
    Hmm I politely don’t agree 100%. Obviously some of the heat will travel up the flue. Mother Nature will pull on the big vertical shaft and whatever opening at the bottom of the shaft is least restrictive, will satisfy mother nature’s requests. So yes it’s wasting heat but not the entire volume of the draft is getting pulled through the heating appliance. I’d say a small portion.

    How much—one would have to get a little focused and measure total volume with a hot tip anemometer at the top of the flue, and then measure the volume entering the hood with the same tool, subtracting one from the other
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
    Dan Foley
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