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propane heater won't stay lit (Vermont Castings Prism)

Maine207 Member Posts: 1
Our kitchen is heated by a propane "decorative appliance" - specifically a Vermont Castings Prism (5340 if I recall correctly) - that came with the house when we bought it. The unit is connected to its own chimney.  For the first two years, the unit worked most of the time, although  occasionally the pilot light would go out and be unable to remain lit.  By jiggling and bending the thermocouple, I was able to restore the unit to service every time - although some times it took hours of  repositioning the thermocouple, sparking it and holding the knob for 10 seconds, watching the pilot die, and trying again.

Then things got worse: the pilot simply wouldn't stay lit. I called for backup. None of the local stove shops were able to fix it; most simply said the unit was older and unrepairable, all without even looking at it. We were able to find two technicians who were willing to come out to the house to see the unit. The first replaced the thermocouple and got it to work for a few months, but soon the same situation reappeared: the pilot light would go out, and then the stove would be unlightable even after extensive thermocouple fiddling. I then replaced the thermocouple myself, with similar results (a few months of operation, followed by ultimate demise).

It's getting cold in Maine. I'd like to be able to heat the kitchen comfortably, especially since our family just widened to take in our newborn daughter.

What are my options?  I'm willing to make the rounds of calling local stove shops again this year, but I'm hoping someone here has an idea that I can either try

myself or suggest to a tech to get this unit to work again.


  • Tim McElwain
    Tim McElwain Member Posts: 4,487
    Has anyone taken any

    millivolt readings on this unit? Is it a straight thermocouple or is a fatter pilot generator?

    Has anyone checked with a combustion analyzer?

    Have your techs check "Resources " above and click on "Hot Tech Topics" then look for "Thermocouple Testing Procedure".
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,200
    I have seen venting issues with these units.

    If the air inlet and exhaust pipe are not connected to the factory termination fitting a back draft occurs and the exhaust goes up the intake pipe, this causes the pilot to go out. also it causes the flame to lift and then go out as the unit runs.
    Cost is what you spend , value is what you get.

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