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Automatic damper bypass dangers or drawbacks?

JerseyJon Member Posts: 17
edited December 2015 in Thermostats and Controls
I have a 3-yr-old Pennco gas boiler with a Field automatic damper (model GVD-5). When I fired up the unit recently it ran normally through the first cycle, but the next morning the house was cold and it was in pilot-only mode.The electrician who wired the controls 3 years ago suspects the damper motor is shot. The things aren't cheap. The local plumbing supply wants more than a couple pictures of Ben Franklin. I could save by buying online, but I would need to wait for delivery.
I see elsewhere on this site that the little toggle switch on the side of the damper control is a temporary bypass switch. If that's true is there any reason I can't just bypass the control and get the boiler running again while I weigh my long-term options?
My boiler is in an otherwise unheated basement, so I don't know how much energy saving I'm getting from closing the damper when the burners aren't on anyway.
So is this an acceptable short term solution?
Is leaving the damper on bypass acceptable for the long term? Seems like it'll be cold soon so any advice is greatly appreciated.



  • Steamhead
    Steamhead Member Posts: 15,331
    First off, we do NOT discuss pricing on this forum.

    The damper bypass is good for temporarily getting the heat on, but not having the damper close between cycles will let both the boiler and the chimney cool down between firing cycles. This is especially true in older houses where the chimney had to be strong enough to pull air thru a coal-fired boiler. So on the next cycle, the boiler has to make up for the heat lost to the open flue.

    On a Field or Effikal damper, it is possible to just replace the damper motor rather than the entire damper. Our company stocks these replacement motors.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • JerseyJon
    JerseyJon Member Posts: 17
    My bad on the pricing. I didn't need to be specific. I was just making the point that replacement is a significant cost and a temporary fix gives me time to decide how best to make the repair and whether it's cost effective to replace or repair.
  • LarryK
    LarryK Member Posts: 46
    I had a problem with the same damper motor. It turned out my Honeywell thermostat was sending some kind of bounced signal back to the motor control when it attempted to complete its open cycle and it would never come to rest. I put in an isolation relay when I changed thermostats and the motor started working correctly. I tested this by jumping the thermostat terminals together and watching the startup cycle. Taking the electronic thermostat out of the circuit made it work correctly.
  • JerseyJon
    JerseyJon Member Posts: 17
    Thanks LarryK. We tried that. No difference. So it doesn't seem to be the thermostat.
  • LarryK
    LarryK Member Posts: 46
    edited December 2015
    Supplyhouse.com has the replacement motor, too.