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Vent Damper Repair (switch replacement)

By on November 20, 2021
vent damper repair







My replacement gas heating system included a vent damper that closes the flu when the gas is not burning to save energy; but it threw a boiler error after just 2 years use. Seems a lot of these units only last 2-3 years and the motor unit alone costs around $100.

how to fix vent damper

I purchased a replacement motor assembly, which meant I had the old one to play with.

It is controlled by three SS-5 micro switches which I suspected even though they tested OK for open and close, but I was not able to test actuation with the notched wheel that governs them (not shown in the picture).

vent damper circuit board repair

The original switches were made by Zippy so I ordered some Omron replacements as I did not want to have to deal with this issue every few years,

let alone the cost of a new motor unit. $10 got me 10 switches on ebay, so I was able to rebuild both the old and new units.

zippy switch

So far, the old, repaired unit seems to be working fine, which is good as I would hate to leave my wife stranded without heating while I am at work (she telecommutes from home); although there is an override switch to force it to stay open in case of failure.

andy sheikh anwar

This article was written by Anwar (Andy) Shiekh originally from London, England; he repairs things to help make an income go further and presently teaches Physics in Colorado, U.S.A.

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Note: You can check his previous repair article on Computer Mouse Repair Switch Replacement




  1. Parasuraman S

    November 20, 2021 at 3:42 pm

    Good fix! Thanks for sharing!

  2. Albert van Bemmelen

    November 20, 2021 at 6:53 pm

    I guess that the notched wheel that governs the 3 micro-switches was not damaged and that only the micro-switches were the problem. Although this was not entirely clear since you also replaced the motor?

  3. Anwar Y Shiekh

    November 21, 2021 at 2:39 am

    I was unclear; the only thing I replaced were the 3 switches, the rest was original.

    Next time I need to take more care with my writing; I appreciated being made aware.

  4. Yogesh Panchal

    November 21, 2021 at 9:48 pm

    Good Jo Anwar


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