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plumb loco

I installed a munchkin 80 that ran great for 5 yrs. lately it has locked out F-05, and F-06 high temp sensors. I suspected air, (system has a spirovent) so I purged the daylights out of it, the problem persisted.  I changed the board and ribbon cable on the boiler, it has been ok for a few days, but I hear air in system.  I'm thinking an air bubble is getting trapped in the boiler raising the supply/ return sensor temp dramatically, and shutting down the system.  Why isn't the spirovent doing it's job? Could it get clogged?



  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839
    I doubt the boiler is air binding....

    I guess anything is possible, but I've never had one get air bound on me.

    If there is a substantial accumulation of combustion products on the fire side of the heat exchanger, you might not be getting the heat transfer you need, and consequently, the flue gas is higher in temperature.

    Have you done a fire side clean and tune in the 5 years?

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • meplumber
    meplumber Member Posts: 678
    Mark is dead on.

    The fire side has to be serviced.  I have seen this once before.  Boiler was installed by others.  I got called when they couldn't fix it.   I found a lot of GOC byproducts on the heat exchanger.  Gave it a good cleaning and tune up.  No more lockouts.
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