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Adding a damper motor to boiler

EdEd Member Posts: 284
This is not a DIY job. Consult the mfg first, to see if the have an upgrade kit. If so, it must be installed & tested/certified by a qualified gasfitter/technician.


  • GeorgeGeorge Member Posts: 20
    Adding a damper motor to boiler

    I have a Utica gas hot water boiler in a 6 unit apartment building. The boiler is from the early 80's and has a standing pilot. I was thinking of installing a damper motor in the flue to increase efficiency. Can I just install it and wire it to the transformer? Would the 10-15 seconds it would take for that damper motor to open be a problem as the burner lights? Any tips or suggestins will be appreciated!
  • JayJay Member Posts: 72
    safety interlocks

    The damper must have a safety interlock with the aquastat which doesn't allow the boiler to fire up if the damper is not open.
    Case in point, last week I came home to a cold house (55F), I went downstairs and looked over the boiler, the pilot was on, the temp was bottomed, there was a buzzing noise. I shut down the power and the gas and scratched my head for a few minutes worried that either the aquastat or the gas valve had crapped out and I was going to have to have an emergency call, when I noticed the damper was half open (or half closed. I pulled the motor and started fiddling when a dead bird fell out of the air intake. Problem solved, it was stuck in the damper.
    Lesson: glad there was a safety interlock, I need a chimney cap.
  • BoilerproBoilerpro Member Posts: 1,231
    Definitely contact the manufacturer....

    Many of the Utica Boilers are the same as the Dunkirks I install. They all have dampers available, I believe, even the large commercial models, which is not the case with most manufacturers.

  • Dave-St LouisDave-St Louis Member Posts: 22
    Vent Dampers

    Energy Vent Mfg. Co. makes these automatic vent dampers that include the safety switchs to be sure the damper is open before the burner fires. Also holds the damper open after the firing cycle, for a short time, before closing.Contact is Marvin Stavig, Stavig Mfg. Co.,Minneapolis, MN, 1-800-581-1911,
    Hope this helps.

    St. Louis Dave
  • That looks like a Utica MGB series boiler

    which almost always comes with a damper these days. Especially with an old chimney that was powerful enough to operate a coal-fired boiler, a damper can make a big difference.

    I'd definitely use the damper kit Utica provides. Also have it installed by a pro. I've seen miswired boilers that allowed the burner to run with the damper closed, releasing flue gases inside the basement. The miswiring also bypassed the blocked-flue switch, so it could not stop the burner.

    Also consider going to electric ignition. This is also a standard feature on MGB boilers and can be had from Utica. Electric ignition is a real plus if the gas pressure varies enough to cause pilot outages in cold weather. With some EI setups, the stack damper plugs right into the ignition module, simplifying the wiring and reducing the chance of malfunction due to miswiring. This change should also be made by a pro.

    Try the Find a Professional page of this site to locate someone near you. If you're in the Baltimore area, contact me.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • JoannieJoannie Member Posts: 45
    Vent Damper For Standing Pilot

    Also, don't forget that dampers for standing pilot units must have a hole in them to allow the vent gases from the continuous pilot to escape.
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