Forum Discussion

swimmer_spe's avatar
swimmer_spe
Explorer
Jun 13, 2020

Furnace not working well

1975 trailer. Furnace issue, but may be a propane issue?

For the last few years, I haven't had a working fridge. This year I finally do, and it works well. For the last few years, the furnace would always heat the trailer well. This year, not so well. It seemed like the furnace wasn't getting enough fuel.

Why would this be the case? We did not plumb in anything that was not already plumbed in. We simply replaced a non working unit for one that did.
  • I would replace the regulator.
    Furnace may need to have orifice soaked in alcohol and cleaned.
  • enblethen wrote:
    Make and model of the furnace?


    Duotherm. I might have the manual on it here. I'll go digging.
  • wa8yxm wrote:
    Furnace not getting enought fuel but fridge works (I assume on propane) Water heater and stove as well. Ok suspect list

    1: Propane tank may have what is called an Excess Flow Valve. This would likely NOT bother Fridge (though one poster said it did) but would water heater and for sure would the furnace if it's closed. If that is the case close tank valve. Pause for oh. about 1 cup of coffee. then SLOWLY open the valve till you just hear gas start to flow.. pause till you don't hear any more flow. Repeat till valve fully open.

    Next is the orifice (The small hole from which stuff spews forth, Gas in this case) there is a spider that loves to nest there.. Clean it out.

    Next is the spark gap on the Direct Spark Ignightor Make sure it's set per the manual

    The Thermocouple normally lasts forever.. but the key word is Normally

    The control board may fry. Mine did. I think I know why.. I replaced it with a Dinosaur board replacement and .... It appears they have the same theory as on the Dino board is a device designed to prevent what I think happened.

    The solenoid valve can also have issues.

    That about covers most of the more common issues. There are a few "Exotic" ones too but those are the most common.

    Oh and the Sail switch..
    To make sure it does not overheat there is a "Sail Switch" when the T-Stat calls for heat the control board starts the blower (I occasionally have an issue there and I have a detector installed for when it happnes) when the blower is blowing enough air the sail switch sails closed and heat is then generated.

    Low battery
    Aging blower
    Clogged ductwork/vents
    Can prevent sail switch from sailing.


    Water heater is not used. Stove may be fine, but couldn't really tell. same with fridge. It did keep things cold.

    The furnace I have is from 1975, so, no circuit boards, ducting or much else. Propane tank is old, but had a new valve installed 6 years ago.
  • Go to You tube learn how to make a manometer, and measure and make adjustments to the propane system, and test the system for leaks. Not rocket science and after a few videos you will be able to figure it out.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Furnace not getting enought fuel but fridge works (I assume on propane) Water heater and stove as well. Ok suspect list

    1: Propane tank may have what is called an Excess Flow Valve. This would likely NOT bother Fridge (though one poster said it did) but would water heater and for sure would the furnace if it's closed. If that is the case close tank valve. Pause for oh. about 1 cup of coffee. then SLOWLY open the valve till you just hear gas start to flow.. pause till you don't hear any more flow. Repeat till valve fully open.

    Next is the orifice (The small hole from which stuff spews forth, Gas in this case) there is a spider that loves to nest there.. Clean it out.

    Next is the spark gap on the Direct Spark Ignightor Make sure it's set per the manual

    The Thermocouple normally lasts forever.. but the key word is Normally

    The control board may fry. Mine did. I think I know why.. I replaced it with a Dinosaur board replacement and .... It appears they have the same theory as on the Dino board is a device designed to prevent what I think happened.

    The solenoid valve can also have issues.

    That about covers most of the more common issues. There are a few "Exotic" ones too but those are the most common.

    Oh and the Sail switch..
    To make sure it does not overheat there is a "Sail Switch" when the T-Stat calls for heat the control board starts the blower (I occasionally have an issue there and I have a detector installed for when it happnes) when the blower is blowing enough air the sail switch sails closed and heat is then generated.

    Low battery
    Aging blower
    Clogged ductwork/vents
    Can prevent sail switch from sailing.
  • 8ntw8tn wrote:
    Could be a bad regulator, as posted above. Or it could be that the regulator just needs to be adjusted. I wasn't aware, until a couple years ago, that the regulator had any adjustment to it. But when our furnace refused to keep running I called the repair guy and that's what he diagnosed. A minor adjustment and all was well. Hope this helps.


    Makes some sense... Is this something I can do? The trailer is a seasonal site in the bush about an hour from a repair shop.
  • Could be a bad regulator, as posted above. Or it could be that the regulator just needs to be adjusted. I wasn't aware, until a couple years ago, that the regulator had any adjustment to it. But when our furnace refused to keep running I called the repair guy and that's what he diagnosed. A minor adjustment and all was well. Hope this helps.

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