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Old 02-08-2021, 11:37 PM   #1
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Furance lights then quits

Hello, I have a problem with my Atwood 15000 btu furnace in my Quantum 26rs. Fan comes on, after the 15 sec wait the gas lights off. It heats/burns for about 2 sec then stops burring (fan still running), after a few sec it tries to light off again. And the cycle continues. As it lights off I am assuming it is not the sail switch. Likewise, as it lights off I am assuming itís not the HIGH temp switch. What might cause it to cycle on / off (gas, fan running), but only run about 2 to 3 sec. HELP PLEASE Thanks

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Old 02-09-2021, 12:09 AM   #2
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There have been many threads on this subject
Start by using the SEARCH function

I had a similar problem when I turned-on the furnace for the 1st time, 4 months after I purchased my rig.

Instead of dropping it off at the dealer, I did the following:
1) removed the external cover, then used compressed air throughout the inner workings
2) when that didnít work, I removed the burner (just 3 screws after disconnecting the propane). I inspected and cleaned everything
3) finally, I adjusted the Spark assembly. Made sure the Spark was ďlongĒ enough (increased it to 3/4Ē). And that the Spark was close to the burner

Once I did all of these things, furnace has worked flawlessly for last 3yrs
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Old 02-09-2021, 12:36 AM   #3
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Since it lights, but then quits you have one of two issues:

The Controller does not "see" the flame which is sensed by the ignitor - could be a bad ignitor even though it lights the gas.

The Controller is "bad". It may actually be a bad controller (common issue) or the board may be wet if you're in rainy weather, also a common problem.

If the Controller is actually bad i recommend you replace it with a Dinosaur board - better quality and longer warranty - probably cheaper as well.
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Old 02-11-2021, 01:59 PM   #4
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I am having the same issue, I actually posted about this also. I did have some water damage on the control board. I replaced it with a Dinosaur board and its doing the same thing, but it may solve your issue. I have an Atwood AFMD 30141. You need to look at the LED on the control board to see the error code. Mine would blink three times indicating an ignition lockout failure.

I would make sure there is no damage to the board, unplug and reseat all the connections. Also there is a switch on the side of the furnace and it called a "sail Switch", I would pull it out (do this slowly it will bend if you are not careful).Make sure the switch is clean and operates fully.

I went ahead and replaced the sail switch on mine, it was less that $20 on amazon.

I am still having the issue but these fixes may solve your problem. I personally like knowing how everything works. I am going to try Taylorbob1's suggestion about the spark adjustment next

Hope this helps!
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Old 02-11-2021, 02:14 PM   #5
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if your ignition is firing (click, click, click...and then a burst of flame for a moment or two), it may be that your ignitor isn't properly located next to the burner assembly
and/or, the ignitor does not have a large enough/long enough spark.

In another thread, it was stated that the spark tongs should not be any wider than 5/8".
However, I spread mine over 7/8" and also moved them closer to the burner
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Old 02-11-2021, 03:18 PM   #6
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Not familiar with Atwood heaters, but don't they have a flame sensor?

I have had flame sensors go bad on other furnaces over the years
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Old 02-11-2021, 03:22 PM   #7
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Originally Posted by lwmcguire View Post
Not familiar with Atwood heaters, but don't they have a flame sensor?

I have had flame sensors go bad on other furnaces over the years
The ignitor is also the flame sensor.
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Old 02-11-2021, 03:38 PM   #8
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The ignitor is also the flame sensor.
So very likely the issue

Thanks
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Old 02-11-2021, 05:54 PM   #9
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Mine will ignite, I could feel the heat but immediately shut off, like it did not sense the flame, I guess it the flame sensor could not work but the ignitor does?
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Old 02-11-2021, 07:05 PM   #10
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Mine will ignite, I could feel the heat but immediately shut off, like it did not sense the flame, I guess it the flame sensor could not work but the ignitor does?
that is sure where I would start, clean it first and if it goes out replace
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Old 02-12-2021, 01:08 AM   #11
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Just an update, I was able to get mine working. I replaced the control board and the sail switch and cleaned all the contacts. Just remember the vent extension has to be in place for the heater to work (I discovered that the hard way...lol!)
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Old 02-12-2021, 01:27 AM   #12
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Glad to see that you found and fixed the problem.
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Old 02-12-2021, 01:48 PM   #13
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One outta two

Quote:
Originally Posted by Bob Denman View Post
Glad to see that you found and fixed the problem.
The OP has not got back to this thread.... But robmc5 did some voodoo on their furnace and now enjoys the warmth.
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Old 02-12-2021, 02:06 PM   #14
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The OP has not got back to this thread.... But robmc5 did some voodoo on their furnace and now enjoys the warmth.
Chronic drive-by poster. Last drive-by thread was 6 months ago.
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Old 02-12-2021, 02:34 PM   #15
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The OP has not got back to this thread.... But robmc5 did some voodoo on their furnace and now enjoys the warmth.
That's where my comment was aimed...
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Old 02-17-2021, 07:25 PM   #16
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Same issue different fix

I had a similar issue.
It coincided with us getting attacked by moths.
Figured I would take the thing apart when I got home.
Get home, it fires right up.
Problem solved.

Next time I go camping, it doesn't work again.
hmmmm.

I email the manufacture and ask them what altitude the heater is rated up to.
I think they said 4,500 feet. Not to great here in California and other parts of the country.

My fix, I moved the igniter tips closer together, not further apart. (Set to the minimum spec)
Has worked above 7,000 feet now.
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Old 02-17-2021, 08:53 PM   #17
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That's where my comment was aimed...
Oh I got that! I was just making comment that the OP left a legacy that robmc5 acted on and won.
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Old 02-17-2021, 09:32 PM   #18
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The OP must have got it fixed. He never came back to respond nor has he even logged in since the 11th.
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Old 02-17-2021, 11:07 PM   #19
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Quote:
Originally Posted by Becauseican View Post
Hello, I have a problem with my Atwood 15000 btu furnace in my Quantum 26rs. Fan comes on, after the 15 sec wait the gas lights off. It heats/burns for about 2 sec then stops burring (fan still running), after a few sec it tries to light off again. And the cycle continues. As it lights off I am assuming it is not the sail switch. Likewise, as it lights off I am assuming itís not the HIGH temp switch. What might cause it to cycle on / off (gas, fan running), but only run about 2 to 3 sec. HELP PLEASE Thanks
YOU MIGHT TRY THIS....we learned from an old camper...when the gas on our refrigerator would not come on..
LIGHT A BURNER ON YOUR GAS STOVE ... it seems to clear the line of any air for some reason...it has worked for us a couple times...IT MAY OR MAY NOT WORK ON YOUR FURNACE...but does not require a lot of effort to try it..
good luck !
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Old 02-17-2021, 11:55 PM   #20
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OP be like Elvis he left the building!
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