RV Furnace Sputters And Goes Out -- Troubleshooting Tips -- My RV Works

[@lanedelker9161]

The Muppets rule! Great information, Darren. Thank you.

[@timberg8640]

Really appreciate you getting right to the point, using great photos and arrow pointers, and having everything ready to show us (not spending time on the video tediously removing screws, etc. Along with sharing your years of experience, you are fun to listen to!

[@cary2677]

Thank you for sharing your knowledge. You help a lot more people out than you may think.

[@doug1olson]

Based on your description I took the burner out of my Dometic furnace and removed the orifice. I did not see anything interfering with the opening but I blew on it, tapped the gas valve in case something would drop out of the openings, but saw nothing. There was still some very fine dust inside & outside the burn chamber left over from a horrendous dust storm we had in AZ two years ago (although the furnace has worked well after that). When I put it back together I thought the gap between igniters and burn chamber was too large so I adjusted the gap smaller. Anyway, after putting it all back together the furnace seems to be working just fine now. Hopefully it stays that way. Thanks for your suggestions.

[@diverm2371]

Always Awesome Darren. Hope you can keep their vids going all winter

[@europro11]

Turned wrenches for almost 50 years. I had the same symptoms on my Atwood furnace. I noticed my cooktop burners were not as high a flame as a few years earlier. My propane regulator full of oil and damaged. Didn’t have to use a Manometer to figure that out. LOL. Replaced my regulator. Cooktop flames got magically higher and Furnace worked every time!!

[@kengroves49]

Thanks for the information video

[@BruniFamilyTV]

I'm having a similar issue with mine. Going to check it out when I get the chance.

[@daviscrt]

Great information. Thanks again Don

[@J.Cameron.Stuart.Adams.]

Excellent info. My neighbors furnace sounds like a Mack truck idling once the gas ignites. The dang thing wakes me up at least ten times a night. Now I'll be able to approach them with a possible diagnosis and offer my assistance to try to fix it.

[@keithgoodrich701]

Thank you Darren, that was a big help

[@somedayistodayrv]

Another new subscriber as well and I am learning some newer things to help in maintenance and diagnosis of issues, thank you for the videos. Take care. Dave.

[@iTookMyShot]

This scenario sounds fairly familiar. I, too, was an appliance tech for over 40 years. My Dometic furnace ( DFMD35141) would fire, not sputter, just extinguish and roughly 15 seconds start again, go out again. No fault codes, no break in the 12v (except after flame out), it would just repeat over and over. Sometimes, after multiple tries, ot would seem to heat "normally" but now, If I take the blower end of my vacuum, and blow air into the blower wheel area (near the burner) it will stay on, as long as I add the air. Also, it seems to do this more at higher altitudes. Presently in Colorado at 7,200 feet. I have not tested with a MaNomiNaa... manometer Spark gap is good, no bugs or debris in orifice, plugged into 110v. Possible restriction in burner intake?

[@twloughlin]

New subscriber here. This is a pretty awesome channel and I am learning a lot. I'm working now to solve a 12v DC issue where I seem to be losing voltage. Your other videos have been helpful so far in learning more about my system. Thanks.

[@chachi5975]

Losing voltage between trips?

[@twloughlin]

@@chachi5975 Losing voltage while boondocking. I turn on two appliances (roof fan and water pump e.g.) and am suddenly down to 3 volts. Then I don't have enough power to turn the 7amp water pump on and things just sort of die. Voltage at the battery remains 13.6

[@chachi5975]

@@twloughlin I would start at the battery and check for a solid connection including the lugs connected to the wire. Then do the same at the circuit breaker/fuse box connection. Depending on your comfort level use the voltage tester I sent you and try to recreate the issue and start checking the voltage starting at the battery and see if you can find where it starts dropping.

[@twloughlin]

@@chachi5975 I'm on that!

[@chachi5975]

@@twloughlin as I read it again, it sounds like something is drawing a lot of power. Can you narrow down item by item to isolate which one is drawing the most power, either the fan or the pump. If one is struggling it will bring down the voltage and may need to be replaced or repaired.

[@DennisWintjes2]

Thanks for sharing. Like #40

[@kirkfarley8516]

New issue creating that problem on Suburban heaters. The fan's are defective. Amp draw MUST be within specs. Otherwise it won't keep the sail switch closed tight.

[@ZiggZagg11]

My Scamp furnace is a Subarban... Hmm 🤔... I wander...? 🤔 👀 (see my previous post}...

[@bigoldal2436]

Great video but miss Romeo. I recommend soaking in alcohol use a toothpick ( wood!!) to clear

[@RoyBower-u7d]

Great video so I learned a lot about the gas valve and igniter. However, my problem was our furnace would start, ignite and then in one second or so, the flame quit. I understand the igniter system serves as a thermocouple, too. Could you do a video on that, too?

[@nickestnickthereis]

Did you ever figure it out? Mine is doing the same thing

[@RoyBower-u7d]

Hi, Nick, Certainly, mine works fine now, but when you are testing the furnace, the exhaust tube MUST be slipped into the furnace. It is easy to remove the tube by removing screws on the outside of the RV. I simply tested the furnace while it was sitting on the floor of the RV. That was easy access to 12v power and the propane connection. BTW; the electrical connection should not rely on the clip-on connectors. Use Wire nuts or solder them! Roy @@nickestnickthereis

[@bigofishon1451]

I have watched many of your videos and find them very helpful. Keep up the good work. I've checked everywhere and can't find an answer to my issue. Hopefully you have some insight. The furnace in our Jayco 5th wheel is a Dometic DFLD40 and it works fine. However, it heats the RV to temp setpoint and the living space cools down right away. I found the furnace return is part of the steps to the bedroom. Looking behind the return vents leads to my cargo bay, plumbing, electrical, etc. (a very large area). In other words, there is no ducting from the return air vent to the furnace. When the furnace is not heating, cold air comes through the return air vent cooling the RV living space. My first thought was to seal off the return air vent. because there is plenty of open space in the cargo bay. But I'm sure if that would be safe. Next, I'm thinking to build a sealed box behind the return air vent and connect ducting from the box to the furnace. But there's no input on the furnace except the slots around the furnace fan.

[@TomasFlores-gm8xq]

or the vent maybe covered with something like a floor mat. Vents could be closed. ext.

[@jeffwebb7702]

I’ve been searching through and watching your excellent and helpful videos. Can’t come across discussion on the issue I’m having though. My Suburban furnace makes a backfire “poof” type sound upon initial shutdown when thermostat set temp is reached. Fan continues to run for cooldown cycle then shuts down completely. Furnace seems to operate normally other than this. Don’t recall hearing this last season. This is in a 2023 Stryker toy hauler. Anything to be concerned with? What could be causing it also? Thanks!

[@RyanMcAnulty-ig1pt]

Hey this refers to the other video with the bad sylinoids so my furnace does everything but I don’t hear a click just the igniter ticking but I think your right it’s gonna be the gas valve or the sylinoids

[@christophermeacham6944]

I’ve looked everywhere through your videos- I can’t find a similar video with my issue- I’ve got an Atwood 7916 ii with a simple 2 wire thermostat. If I put my 10 amp breaker in the buss bar, fan blows, it ignites and and just stays on. Even if I have the 2 wires off the thermostat it runs and heats and doesn’t shut off. The only way I can shut off is to shut off propane cylinder or pull 10amp red breaker. I replaced the board and same thing happened. I also replaced the thermostat and same thing. Thoughts? Maybe the gas valve is stuck open?

[@jasonwyatt919]

Okay so my furnace is similar to this but the difference is after a few time it will finally stay lit. Watched one of your videos and I thought I would try to change the igniter. (Shotgun repair job) worked good after replacing that shut furnace down and used the heat pump for a few days to save propane. Got cold again tried the furnace same problem. Called out a technician he told me my regulators where bad because my high flow was making a screeching noise. Went ahead and replaced both regulator fired it up yesterday after replacing the regulator worked great after getting the air out of the lines. Go to fire it up again today same problem. Fire shut down repeat about 5-6 times then stay lit for the duration of the heating cycle. Also running 100lb propane tanks the tech told me it is hard on the system to use them. I find that hard to believe because it is the same pressure just more capacity. Any help is appreciated. I will check the orifice tomorrow. Thanks in advance. Also when I changed the regulator I found a whiteish foamy substance in the high flow regulator. My father-in-law said that is a lubricant they add to propane?🤷🏼‍♂️ please help I’m about to pull what little hair I have left out.

[@rmendes2mendes915]

My furnace in SF 30 was doing the same thing not getting enough gas to keep the thermal coupler hot enough and the gas would keep shutting off and the orifice was not plugged it ended up being a gas regulator at the tank it was only six months old that for some reason the regulator was sticking inside and not opening enough as the heat coming out of the furnace was not very warm I figured it out when I went outside and took a little wrench and hammered on the regulator went back in and you could see the flame was much larger and the heat went up to the correct temperature this has done that multiple times now until I finally bought a new regulator

[@patrickstiltner1207]

Hey Darren, I've seen you use both types of manometers and a slack tube. Which do you prefer?

[@MyRVWorks]

The slack tube is always my go-to. The accuracy cannot be beaten. Because it's got distilled water, in the winter sometimes that will freeze. So that's when I use the electronic one. The electronic one is consistently off (with no way to calibrate) but when I compare it to the slack tube I believe it's about 2 in of water column consistently. So I can make that adjustment in my mind when I'm performing the tests. The other benefit of the electronic one is I can perform min/max testing for some of these really bizarre LP issues. It's also interesting to see the pressure in different scales. I don't use a dial type at all anymore.

[@LarryLaRue2022]

30 yr HVAC tech here. Buy the alcohol based fluid. Won't freeze. Usually Red color I think.

[@307.William]

I know this is older but I have an Atwood 8531-IV and it’s igniting and turning off. It’ll do this a few times and then give the ignition lockout fault 3 blinks and 3 seconds stop

[@richjoy71]

Why would our DFMD30111 furnace keep tripping the rest button? It fires up blows hot air then trips. The green light on the mother board lights up green initially then turns red when it ignites and is blowing hot air. It’ll run for few minutes to 15 minutes or longer then trips the reset button. Once I reset the button it fires right back up. Any suggestions

[@onemorefarm1535]

I have a furnace. Sotting up, I got low on propane any suggestions clean orfis

[@ronraterman4092]

Thanks for the video. So I have a n Attwood furnace that starts and runs ok but the vents inside do not blow warm. The exhaust is also very fumy or rich smelling. It kinda burns your eyes. The burner and orfice are clean and seems to be in good shape. The camper did not have bug screens on it when we bought it. There were a few dauber nests. I can’t really see the burn chamber Any thoughts ? 08 Jayco 311. I installed a new regulator. It was sputtering and wouldn’t stay lit when we bought it.

[@MyRVWorks]

Besides looking for the insect problem that we address in this video, the next thing would be to do an LP operating pressure and regulator lock-up pressure test at the furnace connection. From your description, it sounds like the furnace is not getting the proper amount of LP pressure to burn properly. To perform these tests it is necessary to have specialized equipment. A competent RV service center should know how to perform these important LP pressure tests.

[@jeffwarhawk517]

My buddy has a momentum 25G toy hauler. He goes camping puts the heater on it runs for a little bit and it will shut off and he’s freezing and he hast to restart it and it will not keep his camper warm any idea

[@BruniFamilyTV]

Ok, I pulled mine apart and confirmed that my gas valve is clear and the solenoids are working properly. Still, the furnace won’t run. It does the click, click, click sound of the spark and it makes heat (and sounds like a running furnace) only while the spark is being made. As soon as the click, click, click stops so does the heat. It does this 3 times and then I get the 3 flashing lights on the circuit board. Mine is an Atwood 8520 iv. I have 11” of WC propane pressure at the furnace (made a manometer) and 12 volts at the solenoids. The voltage drops at the solenoids as soon as the clicking stops. It’s like something is shutting off the gas after a few seconds of trying to light. Even though it does light. It makes heat out the exhaust port. Any ideas?

[@MyRVWorks]

Your DSI board is not able to detect the flame. So you may have an issue with your igniter or you may have an issue with your board. Here's a video that might help you. kzbin.info/www/bejne/ZqWbp4WrfMmNgtk

[@BruniFamilyTV]

@@MyRVWorks thanks. I watched that one before. Is there a way to test the circuit board other than by having a second board on hand?

[@BruniFamilyTV]

(A few weeks later) Problem solved. It was the circuit board.

[@danterryhankinstheexplodin9009]

Also clean the burner itself and the electrodes with a stainless steel brush, it's a frequent problem.

[@mikeRadamz]

Hi Darren, excellent videos, I wish I could call you to work on my motorhome but I'm in Canada, a little out of your locale. I have a couple of 100 lb. tanks with an automatic switchover connected to an extend-a-stay connection that is attached in between my motorhome's tank and the regulator. The problem that I'm running into is that even though the tanks are both full, there is not enough pressure to run the furnace when I shut off the built in tank. Is that because the switchover also has a regulator and do you think that a Fairview GR-9984 High Capacity Automatic Changeover Regulator with a 345,000 BTU's Per Hour Capacity would work?

[@GodBearOutoors]

I have a question, will the furnace fire up and run for a few seconds then shut off if the board is bad? Also, my furnace worked all night after this problem started so would it have done that if it had been the circuit board? Thanks in advance. 👍👍

[@MyRVWorks]

While the circuit board could certainly be a failed component, if the furnace actually ignites and then flames out after a few seconds of operation, that is an indication that the board never detected the flame. That starts with the proper LP pressure at the furnace, the condition of the burner head, electrode gap, the electrode itself as it is embedded into the ceramic housing, the wire from the electrode to the board or finally the board itself. So as you can see, on a flame out, it could be any one of those things that's causing it.

[@GodBearOutoors]

@@MyRVWorks thank you so much for the reply. Very helpful.

[@LarryLaRue2022]

Could it be a bad ground which won't allow flame rectification? Why it lights but won't stay lit?

[@dougnval]

I had similar problem. The furnace would light, run for about 30 seconds, then flame out, and then a minute or so later try to light again. Turns out nothing was wrong with the furnace. We use the gas furnace so infrequently that when I went to use it, there was air in the gas line causing the flame to die intermittently. After I let it run through several cycles of on/off/on/off. I reset it, and it then ran continuously. So before you take it all apart, ask yourself....is there just air in the gas line?

[@alexanderkalesnikoff8566]

Can you make a rv furnace to run continuously?

[@bigofishon1451]

Sorry, message sent befor I finished. Have you come across this return vent issue and to you have any recommendations?

[@ZiggZagg11]

How do I find a qualified rv tech to clean the furnace (I think the jet like you showed here) without driving across the whole country...? 🤔 👀 I callers a mobile rv tech that claimed to work on rv furnaces and he took the front grill off and said it was burning blue and it isn't old enough to anything wrong with it... Camper is a 2021...it is 2024... The furnace is making a gas pop noise and the exhaust is black suit... I noticed that it doesn't gas pop noise as often if I leave vent open a crack... My camper is a small Scamp fiberglass and even the tech said it could be the furnace is starving for fresh combination air... I wanted it fixed, but he just put the front grill back on and said it is working... No Charge...

[@314Captain]

We're also having similar furnace issues, except in our case it seems to only affect us when we're at higher elevation (above 5,000 feet). Once we're below 4,000 feet, the furnace works properly. Any ideas on how elevation might affect our furnace (Dometic DFMD35131)?

[@aguyandhiscomputer]

It'll affect any propane device. Have to look for a high altitude kit. Not sure if they have them for RV furnaces though.

[@unwired1281]

If he gets back to you let us know!