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Outback1990's avatar
Outback1990
Explorer
Oct 12, 2018

Atwood furnace fuel/air mixture too rich

My furnace is blowing smoke and the exhaust is full of soot after only a couple nights use. It's brand new. The intake air on these is forced air by the blower so I'm assuming rather than adjusting air flow, the gas flow is what needs to be adjusted. Anyone know how to do that? I see what looks like a brass set screw on the gas inlet/burner assembly. I've searched the web and YouTube high and low
  • dougrainer wrote:
    pnichols wrote:
    dougrainer wrote:
    1. There is NO air/mixture adjustment
    2. You state black soot. That means you have a inlet fresh air restriction which is usually a Mud dauber nest or insect nests. Don't care if you state new, the insects can get inside on day 1 or on the Dealers lot.
    3. The furnace will have to be pulled to verify the problem. IF insect nests, NO WARRANTY from the OEM or Atwood. If this happened at the dealer, then you would have to go back thru him. Doug


    Hmmm ... can't the OP just take the outside furnace cover off and run something flexible back and forth in the burner tube to clean out any insect stuff?

    I've looked at my Atwood furnace and it seems easy enough to do. I actually did this to my hot water heater burn tube to clean it out after black smoke dirted up the outside of our RV above the hot water heater burner vent outlet. It was easy to do.


    No, the Water Heater is just a short tube. The furnace has various chambers with sharp turns. Plus, the odds are the problem is close to his burner, which can only be serviced or checked by pulling the RV unless he has a model with an outside access door and the valve/burner can be pulled, but not likely he has that model on a new RV. Doug


    Thanks for the clarification!

    I guess I assumed the only correct way to design an RV was to have somewhat decent outside access to the propane furnace - like our 2005 Itasca does - and thus the OP's naturally would. Unfortunately, maybe a bad assumption on my part.
  • pnichols wrote:
    dougrainer wrote:
    1. There is NO air/mixture adjustment
    2. You state black soot. That means you have a inlet fresh air restriction which is usually a Mud dauber nest or insect nests. Don't care if you state new, the insects can get inside on day 1 or on the Dealers lot.
    3. The furnace will have to be pulled to verify the problem. IF insect nests, NO WARRANTY from the OEM or Atwood. If this happened at the dealer, then you would have to go back thru him. Doug


    Hmmm ... can't the OP just take the outside furnace cover off and run something flexible back and forth in the burner tube to clean out any insect stuff?

    I've looked at my Atwood furnace and it seems easy enough to do. I actually did this to my hot water heater burn tube to clean it out after black smoke dirted up the outside of our RV above the hot water heater burner vent outlet. It was easy to do.


    No, the Water Heater is just a short tube. The furnace has various chambers with sharp turns. Plus, the odds are the problem is close to his burner, which can only be serviced or checked by pulling the RV unless he has a model with an outside access door and the valve/burner can be pulled, but not likely he has that model on a new RV. Doug
  • dougrainer wrote:
    1. There is NO air/mixture adjustment
    2. You state black soot. That means you have a inlet fresh air restriction which is usually a Mud dauber nest or insect nests. Don't care if you state new, the insects can get inside on day 1 or on the Dealers lot.
    3. The furnace will have to be pulled to verify the problem. IF insect nests, NO WARRANTY from the OEM or Atwood. If this happened at the dealer, then you would have to go back thru him. Doug


    Hmmm ... can't the OP just take the outside furnace cover off and run something flexible back and forth in the burner tube to clean out any insect stuff?

    I've looked at my Atwood furnace and it seems easy enough to do. I actually did this to my hot water heater burn tube to clean it out after black smoke dirted up the outside of our RV above the hot water heater burner vent outlet. It was easy to do.
  • Outback1990 wrote:
    I can't believe they don't put filters on the intake or inside air vents. My first rv



    If this is your first experience with an RV, be prepared for a lot more "I can't believe........" in the future. ;)
  • Thanks for the responses. I'll end up having to warranty repair it then. I was just hoping for a quick and easy fix without having to tow it all the way to the dealer. I tried to check the intake but the blower cover is in the way and from the looks of it, requires the entire unit to be pulled to remove it. I can't believe they don't put filters on the intake or inside air vents. My first rv
  • 1. There is NO air/mixture adjustment
    2. You state black soot. That means you have a inlet fresh air restriction which is usually a Mud dauber nest or insect nests. Don't care if you state new, the insects can get inside on day 1 or on the Dealers lot.
    3. The furnace will have to be pulled to verify the problem. IF insect nests, NO WARRANTY from the OEM or Atwood. If this happened at the dealer, then you would have to go back thru him. Doug
  • Check the intake for obstructions. Other than that, since it's new I'd let warranty take care of it.
  • If it is "brand new" have it looked at by a qualified person, under warranty.
  • Verify your inlet pressure first. If the inlet is too high it could cause sooting.

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