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Guardian 90 PLus Furnace

kensyme Member Posts: 3
edited September 2020 in THE MAIN WALL
First start up. Furnace has 5 propane burners. On start up, the burners on each side of glow igniter with start burning. Flame won't transfer to other 3, then shuts down, no flame to flame sensor. I can light the other 3 burners with bbq flame stick on start up, then furnace will work. Checked gas pressure before valve, have 8 oz. of pressure. Burners are horizontal, and up draft.


    JUGHNE Member Posts: 11,021
    Are you the home owner or in the trade?

    By first start up do you mean for the season or new install?

    Was the furnace properly converted to LP from NG?
    That includes the gas valve regulator spring, main burner orifices and pilot orifice if any.

    What pressure is on the manifold side of the gas valve?

    You are getting primed for delayed ignition of the main burners.....this is something that will get your attention and remove your beard.....this I know. More drastic with LP than NG.
  • kensyme
    kensyme Member Posts: 3
    I'm the home owner, I installed the furnace 8-9 years ago. I do all the maintanence on this furnace. This is first start up of 10 season. When I start the other 3 burners with lighter stick, it will work for the morning, kick on 3-4 cycles. Turn it off for the day, it won't light next morning without help.
  • kensyme
    kensyme Member Posts: 3
    Will have to check pressure after valve. Haven't had chance yet.
  • Ironman
    Ironman Member Posts: 7,336
    8 oz. of pressure?
    Gas pressure is measured in inches, not ounces.

    Is this natural or LP?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    JUGHNE Member Posts: 11,021
    At 10 years it could be orifice's partially plugged and/or most likely plugged carry over/cross over-- track/ribbon that is perpendicular to burners.

    Kens.....I am sure you are aware of this:
    However, just a reminder to any one else reading this......propane is heavier than Natural gas. It can accumulate in the bottom of the furnace, whereas NG will vent up out the exhaust system.
    If no source of ignition it can come out onto the floor looking for your water heater pilot.........this is as serious as a heart attack.
  • unclejohn
    unclejohn Member Posts: 1,833
    Most propane is 11" at inlet to gas valve and then manufactures instructions for burner side. I would first pull and clean burners and check for spider web in orifices. Then get your propane supplier to check and set pressures.
    JUGHNE Member Posts: 11,021
    Am I remembering right that 8 ounces is 1/2 PSI.
    1 PSI is 28" WC, so he has half of that being 14" WC.
    Gas valve max is usually labeled at 1/2 PSI inlet.
    Furnace label or book would show correct outlet pressure to the manifold/burners.

    Yes incoming should be 11" WC for LP, perhaps his gauge is not accurate enough. And the 14" could be with no load that may drop a little with firing.

    But to check and adjust manifold pressure the WC gauge would be the best.