Heater not working

[UNISOL]

Good morning, woke up in 20 degree weather with no heat. Usually use electric at night, but like to turn RV heater on first thing in the morning. Here are the specifics:

1. Both tanks are almost full.
2. There is air flow through the vents.
3. The furnace is making the sounds, as if it were attempting to light but not getting the fuel needed.

I am of the mind it could have something to do with the regulator attached to the pigtails outside, but will have to wait until this afternoon to check. Maybe it is dirty. I was able to cook and use the heater as of last night, but this morning the heater would not work. I did not check the stove. 2013 Keystone Raptor Toy Hauler. Thank you for any help / guidance, gonna be freezing here over the next few days.

[JRTJH]

Do the water heater and stovetop light properly? If so, you may have a furnace problem. If they don't light either, it's a propane issue.

[UNISOL]

Hot water was working, but did not get the chance to check the stove this morning. Like I said earlier though; the furnace is making the normal noises it would if it were trying to ignite, but acts as if it is not getting sufficient fuel. Thank you for your response.

[sourdough]

You will need to verify that you have propane flow to the stove and it works properly. Your water heater would give you hot water if it's running on AC.

If it's making the normal noises but won't ignite it sounds like 1) lack of fuel, 2) bad board or 3) something is dirty. Did you move or change the regulator (tank)?

[UNISOL]

First off; on 50 years of marriage, that is truly awesome! Secondly, I am tracking all of what you said, save the bad board portion. I checked the fuses and they were good, are you referring to the circuit board??

[sourdough]

First off; on 50 years of marriage, that is truly awesome! Secondly, I am tracking all of what you said, save the bad board portion. I checked the fuses and they were good, are you referring to the circuit board??


Thank you. Yes, I was referring to the circuit board. Mine acted similarly once upon a time but it did ignite for a second, then shut off. Had to replace the board. Yours really sounds like a propane issue but if everything else works it's either the board or the burner/ignition system seems to me. I'm sure others will chime in with their thoughts as well.

[JRTJH]

Propane turns to a gas at very low temperatures but it slows down significantly at temperatures below about 20F. The less propane in the tank, the less liquid that will turn into gas and flow to the regulator. Next is the regulator, probably the most "sensitive" part of the system. Any water vapor in the regulator can cause it to stop flowing propane in the gas form. So, if the regulator gets "iced up" (something that happens in high humidity on cold nights) it may stop the flow of propane in the line to your appliances. That's why we're asking if the stove/water heater were operating normally. The water heater, as sourdough said, can be operated on electricity or propane (or both) and the tank will stay hot for several hours after propane stops flowing, so having hot water to wash your hands may not be an indication of anything not working properly on the propane side of the water heater. That's why I asked if the stove was operational.

Keep in mind that when you get back to the trailer this afternoon, if the sun has warmed the regulator, you may find that everything operates normally and will continue to do so, until the temperature falls again. The next time (hopefully it won't happen) but.... the next time the furnace stops working, try to determine if you have propane flow to the stove burners. If you do, then you have a furnace problem, probably the circuit board, but, on the other hand, if you can't light a stovetop burner, it's probably a problem with the propane flow, possibly the regulator.

[PARAPTOR]

Good information from others, only thing I would add is when you check that stove I would turn on all burners at once to simulate the flow required by the furnace. Good Luck

[Old soldier]

Same basic in in our 2018 Montana High Country 310re. Ours would start-stop-start-stop and if it blew any air, it was cold. Found we had to turn the thermostat off “auto” (for the heat pump). Had heat, but still intermittent. Technician found Keystone used a “self healing fuze” (15 amp, dark blue color) on the furnace (slot #6 on our panel). Never heard of one before. Turns out they can reset themselves like a circuit breaker. He pulled it out and replaced with a standard 15 amp. Had heat OK, but we still have an electrical issue. Nudge your fuze to see if you get a spark....you shouldn’t, but might. We do. Bad connection in the converter panel. Regulators can fail or wear out, but are so simple it’s not likely an issue. Only had to replace one once in our 1964 Fireball vintage camper, for example. That was old! Make sure you “point” the switchover knob/arm to the tank you want to use. You can leave it in the middle position, but won’t know your level is out until the furnace won’t light. Furnaces take a lot more gas than a stove even with all burners going. But turning them on helps prove the gas is flowing after tank switches for refills. There will also be air in the line, so make sure you run the burners long enough to bleed the system. Good luick.


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[rhagfo]

We had a similar issue stove worked fine, knew furnace was good as I had it bench tested just before as it had a strange flame noise at times. Didn’t check WH as run on both electric and gas. Replaced the regulator and all is great.

[ChuckS]

Suburban furnace.. I assume..

After three attempts it will go into lockout mode. To clear the lockout turn the thermostat completely OFF and wait a minute.

Now try the furnace again.. blower should come on, listen outside and see if you hear the electronic spark firing..

If you do then this tells you the Sail switch is functioning correctly but the gas valve is not opening..

In this case then you either have a propane supply issue, defective propane control valve on the furnace, or defective module board.

Unfortunately Suburban modules don’t have the diagnostic LEDs to aid in your troubleshooting.

[ChuckS]

Lookin at age of post guess the fella got the furnace to light


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[JRTJH]

Lookin at age of post guess the fella got the furnace to light


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Yup. The OP posted his initial question and the two followups on 12/28/17 and signed off immediately after the final post (his only three posts on this forum). He has not signed onto the forum since then, so chances are he found the answer and "moved on"....

[jalad12]

Same basic in in our 2018 Montana High Country 310re. Ours would start-stop-start-stop and if it blew any air, it was cold. Found we had to turn the thermostat off “auto” (for the heat pump). Had heat, but still intermittent. Technician found Keystone used a “self healing fuze” (15 amp, dark blue color) on the furnace (slot #6 on our panel). Never heard of one before. Turns out they can reset themselves like a circuit breaker. He pulled it out and replaced with a standard 15 amp. Had heat OK, but we still have an electrical issue. Nudge your fuze to see if you get a spark....you shouldn’t, but might. We do. Bad connection in the converter panel. Regulators can fail or wear out, but are so simple it’s not likely an issue. Only had to replace one once in our 1964 Fireball vintage camper, for example. That was old! Make sure you “point” the switchover knob/arm to the tank you want to use. You can leave it in the middle position, but won’t know your level is out until the furnace won’t light. Furnaces take a lot more gas than a stove even with all burners going. But turning them on helps prove the gas is flowing after tank switches for refills. There will also be air in the line, so make sure you run the burners long enough to bleed the system. Good luick.


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I am going through the very same issue now. The heater worked for an evening and cycled several times. I woke up and the temperature was well below the set temperature. I had propane and the stove worked. I checked the breakers and nothing was tripped. I then checked the fuses and saw a 15 amp black box-type fuse in the furnace slot (slot6). I pulled it and saw that I couldn’t see the filament. When I plugged the fuse back in it was a tight fit ( maybe it was my fat fingers!) and there was a spark when I tried to push the fuse back in. The furnace immediately fired up and blew hot air. After it reached temperature and turned off, about 15 minutes later the temp dropped and the furnace kicked back on. This time there was no heat and it was blowing cold air. It stopped on its own and didn’t fire up again. Should I replace the fuse with a standard 15 amp fuse?

[Mmeyer]

I had the same problem. I replace that black fuse with a standard and its been working perfectly now for 1 year, My dealer said it is a common problem, The black wider fuse has relay built into it and that is the problem I was told. Hope this helps

[jalad12]

Thanks! I’ll give it a try once I’m done drinking my Bloody Mary!! �� (Hey, I’m camping and it’s Sunday!). I’ll send a follow up later!

[jalad12]

I tried the furnace with the black fuse and the blower came on but the furnace did not ignite. I replaced the black fuse with a standard 15 amp fuse and had the same result. Blower was blowing cold air. Propane was sufficient and the stove ignited. My 2019 Cougar (Res 27) is still under warranty. Unless someone has a quick and easy fix I’ll have to bring it in to the dealer. We have plans to camp in the Phoenix area at Christmas so I hope it will be fixed by then. My last warranty repair with the dealer took an exceptionally long time.

[jalad12]

My dealer is booked through the holidays. I have an appointment the first part of January. The furnace problem is nothing a couple of space heaters can’t solve (with proper ventilation, of course)! Thanks to all for your input and advice! Enjoy the holidays and happy camping!

[mm01moose]

I own a 2020 Keystone Raptor 356. Trying to troubleshoot, as to why my propane heater will turn on but will not ignite and then will click off. The propane tanks are full and stove works. I pulled outside cover and hit reset switch and it started and reached temp and when it turned on again it would not ignite. Checked black 15 amp fuse and then switched it to a blue 15 amp fuse. It ignited and then it reached temp and turned off but it would not ignite back up when heat turned it on. Do I need to check sail switch? Any advice as what could be wrong? I just had the year warranty work done and dealer stated everything worked correctly. Any assistance would be greatly appreciated!

[jalad12]

From what I’ve read, it’s either the fuse, the sail switch, the temperature sensor, the circuit board or the LP solenoid. I pulled my furnace and am sitting in front of it right now. The reset switch was not tripped. The sail switch was clean and not bound up in any way. I can see the circuit board, and the red light, but I need to apply power to the unit to see if the red light turns on. If it doesn’t, I think it’s an indication that I need a new board. I’ll give an update when I do that.

[jalad12]

So I disconnected the liquid propane from the furnace and removed the furnace. I checked the sale switch and it was clean and operational. I tested it for continuity with my multi meter and it tested OK. I noticed however that there were wood shavings in the area around the furnace as well as charred wood shavings in the furnace immediately below the exterior exhaust port. I’ve vacuumed these areas immediately. I turned on the furnace without hooking up the propane just to see what would happen. The blower started and I clearly heard the clicking of the igniter. The igniter cycled three times before the entire furnace turned off. At this point the red light on the circuitboard was flashing three flashes every three seconds. According to the sticker on the furnace this was an indication that the ignition was bypassed. I turn the unit off at the thermostat and 3 to 5 seconds later I heard a click at the air-conditioning unit. If everything I read is correct this is an indication that the furnace was now reset. I Placed the furnace back into its location and reconnected the ducks and the liquid propane line. I turned on the propane at the tank and turned on the furnace at the thermostat. The furnace worked properly and the propane ignited and before too long I had heat. I adjusted the temperature at the thermostat to see if the furnace would turn off on its own. I cycled the furnace three times in this manner and each of the three times it turned off and then back on. It worked properly all three times giving me heat.

I don’t know what I did to get it to work. Perhaps vacuuming the debris from inside helped or perhaps moving the wires around and making sure the connections were tight possibly could’ve done something. As it stands now I’m taking the unit out during Christmas week and I’ll test it before we leave. I will not however cancel my appointment with the dealership in case the problem flares up again while we’re on the road. Thanks to everyone for your input and if you think you have an idea as to why it started working again please let me know thank you

[JRTJH]

Someone several months ago was describing the process they went through removing, checking and reinstalling their furnace. I remember one comment they included in their description: "There was a decal on the side of the furnace case that said "Hit here with hammer" (or something along those lines)...

While I don't know for sure if there really was a decal on the furnace case, it does bring to light a well known "troubleshooting technique":

If all else fails, use a bigger hammer.......

In your situation, you may have "reseated the loose connector or plugged in the loose wire or freed up the binding sail switch or ????? In any case, you may never know what "fixed" your furnace, but as long as it's working, another old saying "rings true":

Don't look a gift horse in the mouth.....

Glad you got it working, hopefully you'll stay "toasty warm" on that trip !!!!!

[jalad12]

:D. You are correct! It’s working and that’s all I care about (no hammer necessary)!

[bobbecky]

You also might make a note, that your propane lines are strictly propane gas in its gaseous state, not liquid. No where in your trailer should you have any liquid propane except for in the propane cylinders.

[jalad12]

You also might make a note, that your propane lines are strictly propane gas in its gaseous state, not liquid. No where in your trailer should you have any liquid propane except for in the propane cylinders.

Thanks! That was a faux pas on my part. I know it’s gas, I wrote LP as a short cut. You make me realize that others read this and I should be as accurate as possible to avoid confusion.

[mm01moose]

I pulled the sail switch and cleaned it up with air hose attachment and installed it back into the chamber and the heater worked. I tested it twice to make sure it turned off and then on again without making the reset switch turn off. Hopefully it will work like it should this evening when the temperature drops. Thanks everyone that helped list suggestions regarding having heating issues! This forum definitely helps us diy to fix things ourself without paying the outrageous cost per hour for RV Repair! Merry Christmas!

[LHaven]

I own a 2020 Keystone Raptor 356. Trying to troubleshoot, as to why my propane heater will turn on but will not ignite and then will click off. The propane tanks are full and stove works. I pulled outside cover and hit reset switch and it started and reached temp and when it turned on again it would not ignite. Checked black 15 amp fuse and then switched it to a blue 15 amp fuse. It ignited and then it reached temp and turned off but it would not ignite back up when heat turned it on. Do I need to check sail switch? Any advice as what could be wrong? I just had the year warranty work done and dealer stated everything worked correctly. Any assistance would be greatly appreciated!

So it always works the first cycle but never the subsequent cycles? My go-to answer of "it's the sail switch" may fail me here.

Do you hear the snap-snap-snap of it attempting to ignite, or not? If it's snapping, the sail switch and temp sensor should be OK, and you should look for a propane feed problem. If not, I'd rank the possibilities as temp sensor, circuit board, and really creative fouling in the sail switch (to work the first time but not afterwards).

Edit: Sorry for chiming in late, I plumb missed seeing there was a second page to the thread.

[ChuckS]

The one issue with “cleaning” the sail switch is... you can’t possibly clean the small contacts inside that relay.

You can remove dust and animal hair and such BUT... the contacts have most likely arced a bit because of the interference from the junk that prevented sail switch paddle arm from moving far enough to depress that micro switch and properly close the contacts.

They are pitted and now have a higher resistance then clean new contact surface would... this in turn will only continue to increase in resistance and the sail switch will soon not be able to properly complete the electrical path to complete the circuit...

I’d order a new sail switch and have on hand

[gkainz]

My first go-to response to troubleshooting the furnace (any gas appliance, actually) is "check and clean the nozzle" ... spiders LOVE to spin webs in or near the outlet. Doesn't take much of a web to screw up the gas flow enough to not light or cause inconsistent behavior.

It's also WAY easier than checking the sail switch, testing the board or pulling the furnace to bench test.

I have to disassemble and clean the gas nozzle on my gas smoker at least every spring or I get a really smokey yellow flame.

A buddy just threw a WHOLE bunch of parts on an indoor gas fireplace/stove in his mountain cabin only to finally clean the jet with good results. He's now got a tool box full of spare parts.

[ChuckS]

But in an RV furnace unless it has an outside access panel you can’t get to anything without pulling the furnace ... the burner assy is buried inside with the ignitor/ flame sensor

[jlonginav]

I had the same issues being described in this thread. Last spring I changed out the control board for a Dinosaur version. So far this winter, no issues

[jasin1]

I am a residential hvac contractor. I have very little experience with rv systems. Most here know more then I do. I did notice that suburban furnaces control boards look for a minimum of 9.5 volts at the board in order to work. If not it goes into standby mode until it see’s at least 9.5 ...I wonder if ground issues can cause low voltage intermittent problems at the furnace