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Author Topic: Furnace burner fails to burn ignite coninuously  (Read 405 times)

rollingblunder

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  • Posts: 25
Furnace burner fails to burn ignite coninuously
« on: December 08, 2017, 08:18:42 PM »
Problem - (The short version)
Atwood (Dometic) burner fails to run continuously to temp set on thermostat. There is a history.
At first failed everywhere. Would burn for a few seconds, go out, burn again a little longer, go out. Pattern continued for 6 - 10 cycles progressively longer up to several minutes but still not right. Brought to dealer - they removed approximately 15' of duct coiled under sink.saying it was causing shut- off.
This sort of corrected problem could get to run longer ( same cycling as above). Got to thermostat setting. Brought it back to dealer and was told it sort of works fine here but if you have problems on road others can look at.
BUT
Then we figured we could limp along - Needed heat in Santa Fe (7000+ feet)- Worse cycling than original = several seconds at best. Called service Tech - Very informative "Oh Yeah - Atwood , need elevation kit".
Had Dometic send kit to next location - So. Cal (-50' Elevation). Had kit -( A 1" longer exhaust pipe) installed. Didn't need heat but tried it out - System still cycled erratically - but got to burn for several minutes.
Now on return - at elevation 4500' need heat - cannot get to burn for more than a few seconds. Trying to make alternative provision so we don't freeze up. Help!!!
Anybody know what could possibly be wrong so we can tell the techs what to look for. Dometic and manufacturer of RV seem clueless. (RV is brand new  2017.
Thanks as usual

bross

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  • Posts: 321
Re: Furnace burner fails to burn ignite coninuously
« Reply #1 on: December 09, 2017, 08:21:25 AM »
Make sure you don't have anything restricting gas flow to the furnace. I have an extend a stay set up on my RV so I can supply the furnace from a 30 lbs portable tank. I installed an in line tank level gauge on the propane line at the tank so I would know when it needed refilling. When I did that, I had the same problem. The gauge caused enough of a flow restriction in the gas line that the furnace would shut down because of low gas pressure, then it would start back up because the pressure would build back up when the burner shut down. Anything restricting flow in the propane line would do the same thing. 
Bill & Doris
Winnebago Adventurer 38Q

spencerpj

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  • Posts: 73
  • Indianapolis, IN
Re: Furnace burner fails to burn ignite coninuously
« Reply #2 on: December 09, 2017, 09:04:40 AM »
Sounds like possible heat shut off safety sensor of some sort.  Is your exhaust fine? I know in home furnace, if chimney is blocked, there are sensors that say, whoa, getting too hot, chimney blocked.
2005 GMC Yukon XL, 1500, 4WD
2012 Puma, 19fs

Punomatic

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  • Posts: 550
    • Life in Black and Blue
Re: Furnace burner fails to burn ignite coninuously
« Reply #3 on: December 10, 2017, 09:57:24 AM »
Here is a link to Bryant RV Services. They have a ton of online owner's manuals, service manuals and troubleshooting information. If I were you, I would carefully peruse the site and see if you can find your model of furnace. Learn everything you can about it, and then start troubleshooting. As the Bryant owner says, "you need to understand how a system works before you can determine why it isn't working."
2016 Riverside White Water Retro 195
2014 Nissan Titan SL Crew Cab
DW and me and Pogo (the neurotic terrier-gone to the rainbow bridge) and Lulu (the Moxie with moxie)

Leonard Timm

  • Posts: 4
Re: Furnace burner fails to burn ignite coninuously
« Reply #4 on: December 29, 2017, 05:21:17 AM »
I had a bad regulator that allowed the stove to run but, provided insufficient pressure to the furnace for it to ignite.  Replaced it and everything works fine.

rollingblunder

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  • Posts: 25
Re: Furnace burner fails to burn ignite coninuously
« Reply #5 on: January 04, 2018, 12:15:50 PM »
Thanks to all - still working on problem with Dometic and technician. There have been a series of minor problems resolved that all could lead to the dilemma but still checking other discrepancies (all seem to be installation related and not unit issue).
P.S. - of course we had all manuals and product information as well as online info during investigation

allenb12

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  • Posts: 22
Re: Furnace burner fails to burn ignite coninuously
« Reply #6 on: January 04, 2018, 04:55:07 PM »
It does sound like it could be a bad high limit switch.  It also could be a bad thermostat.
2015 Rockwood 2604WS
2012 Ford F250 Diesel Super Duty
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