Suggestions on why heat didn't work on trip a year ago. Don't want a repeat.

[Evereddie]

One year ago in Feb we took a trip from NC to Florida in our Rockwood 2306. Stopped for a short overnight in Walmart somewhere in South Carolina. It was very cold/damp and we needed to run the furnace. As hard as we tried it would not light. Made all the right sounds but no flames. We have used it a few times in the past so I know it works and I had tested it before we left and all was well. Trailer voltage was normal, and the stove right next to the furnace worked fine. We ultimately used the stove very carefully with proper venting for a few minutes (stood right next to it the whole time running) to get some heat.

Doing a similar trip in a few weeks and don't want to recreate last years problem. What might this have been? Cold damp air getting into the furnace exhaust and intake ports? Maybe I should cover it with something until we need it. Will also pack my tent heater we used in days gone past. It has a catalyst burning element and much more appropriate to run inside. Still need venting but not like running the stove.

Shoot! Hate that you can't fix a typo in the title of the thread.

[geotex1]

Easiest thing to try first - blow the soot out of it. The outside heater vent - one side is an intake, the other exhaust. Force air from compressor or leaf blower in one side and stand clear as soot will launch from the other. If that doesn't work, a spider or mud dauber may have plugged up your propane flow.

[KyDan]

Intermittent operation of an appliance is a pain to trouble shoot.

Have you tried it lately??? You don't mention if it's working now or not
so we're really in the dark without more information.

Could be insects in the flue or bad control board or other problems.

My furnace became intermittent last winter and I wound up replacing
the control board but I did a bunch of trouble shooting before I went
that far. Also my unit was 6 years old at the time.

Does it work now?? How old is your unit? Make and model of furnace?

[Kaadk]

Longshot since I haven't heard of this before, but would make sense as a safety feature:

Were you hooked up to the truck? It might be possible there's an interlock of some kind to prevent the furnace from running when connected to prevent it from running while going down the road.

Like I said though, that's a long shot since I've never heard of such a feature before.




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[caper]

Did the fan start? If the fan was running it might not have had enough speed to activate the sail switch. Your battery could have been low and not had enough power get the fan up to speed.

[KyDan]

Originally Posted by Kaadk

Longshot since I haven't heard of this before, but would make sense as a safety feature:
Were you hooked up to the truck? It might be possible there's an interlock of some kind to prevent the furnace from running when connected to prevent it from running while going down the road.
Like I said though, that's a long shot since I've never heard of such a feature before.
Sent from my iPhone using Forest River Forums

There is no such thing as a furnace/vehicle attached interlock.
You can run the furnace whether plugged in or not.
No one here recommends running the furnace while moving but
you could if you wanted to but we don't recommend doing that!
In fact- I've run my furnace while plugged in several times in order to
get a little more run time out of low batteries in the trailer.
(We were NOT moving at the time!)

[Brother Les]

trouble shoot now while you are at home. Recreate the same conditions. Not plugged to truck, not plugged to shore power. Battery fully charged and terminals clean. Your fan must come on before the burners will light. Remember that there is air in the lines that must be allowed to purge out and this may take awhile.

Also, using a (back) burner on the stove to cut down the chill is just fine and you don't have to stand next to it to get heat off it for the whole room. I would never leave a stove burner on or the furnace on when boonedocking when I retire for the night. (safety first and always)

[Evereddie]

Update, more info. Sorry I didn't finish the original post. Hit send before looking at it so here is more.

The next morning I tried the furnace before leaving and it worked! Maybe the stove heat and heat from the 3 of us inside defrosted something. It has worked since. We were plugged into the tow vehicle and battery charge level was at 100 %. We have used it very little so don't think there is a chance it has soot build up. Have has a insect protector screen on it from that start. Trailer was bought new in March, 2013,

Guess it is just a perfect storm of driving in very cold, wet conditions.

[Evereddie]

Originally Posted by Brother Les

Also, using a (back) burner on the stove to cut down the chill is just fine and you don't have to stand next to it to get heat off it for the whole room. I would never leave a stove burner on or the furnace on when boonedocking when I retire for the night. (safety first and always)

Yes, my point was that I didn't want to lie down and take a chance of falling asleep while the burner was running. I didn't really stand right next to it, just didn't take any chances.

[geotex1]

Originally Posted by Evereddie

Update, more info. Sorry I didn't finish the original post. Hit send before looking at it so here is more.

The next morning I tried the furnace before leaving and it worked! Maybe the stove heat and heat from the 3 of us inside defrosted something. It has worked since. We were plugged into the tow vehicle and battery charge level was at 100 %. We have used it very little so don't think there is a chance it has soot build up. Have has a insect protector screen on it from that start. Trailer was bought new in March, 2013,

Guess it is just a perfect storm of driving in very cold, wet conditions.

Arm-chair diagnosis based on this additional information is the likelihood propane line needed to purge. Routing of lines can make this a slow process. Might want to make a practice of firing it each trip to confirm operation. Where I live, this is just religion since insects and spiders love the furnaces and hot water heaters.

Happy Camping!

[KyDan]

Originally Posted by geotex1

Arm-chair diagnosis based on this additional information is the likelihood propane line needed to purge.

Agreed! When my rig has been sitting idle with LP off I always turn on
the tanks and light a stove burner to get air out and gas flowing.
Then I light the water heater just till I hear it light then shut it off.
Only then do I try lighting the fridge.
Furnace would be next if I were testing but usually don't light it unless
we know we're going to need it on that trip.

I think you're probably OK.

Happy Camping!

[Evereddie]

Appreciate all of the help. I have ruled out many of the things brought up here since we were traveling with the refrigerator on gas, I tested the furnace a few days before and it was good, when the furnace flame didn't start (the fan ran as normal) the stove ran immediately when we turned it on. It still feels like it was somehow frozen and after a night of warming the inside of the trailer it fired up immediately the next morning. But I will say I think that the propane was turned off for about a day after the furnace test at home and that may be the issue despite having everything else propane related on after that. (stove, refrigerator)

It's going to get down to 24 degrees tomorrow night and 15 degrees in a week. I am going to fire it up both nights to see if I can find out anything. Will report back.

Thanks again for every bodies help and suggestions.

[Flybob]

There is a safety feature that trips once there have been several fail tries to light. If there is air in the line, the furnace will not light until after a few tries. This causes the safety feature to trip. Once this happens, you must turn the furnace off ( remove power not just turn down) to reset. In most cases this can be done by turning the thermostat to off. Light the stove and allow it to burn for a while, reset the heater and try again.

[Ham Camper]

Originally Posted by Evereddie

One year ago in Feb we took a trip from NC to Florida in our Rockwood 2306. Stopped for a short overnight in Walmart somewhere in South Carolina. It was very cold/damp and we needed to run the furnace. As hard as we tried it would not light. Made all the right sounds but no flames. We have used it a few times in the past so I know it works and I had tested it before we left and all was well. Trailer voltage was normal, and the stove right next to the furnace worked fine. We ultimately used the stove very carefully with proper venting for a few minutes (stood right next to it the whole time running) to get some heat.

Doing a similar trip in a few weeks and don't want to recreate last years problem. What might this have been? Cold damp air getting into the furnace exhaust and intake ports? Maybe I should cover it with something until we need it. Will also pack my tent heater we used in days gone past. It has a catalyst burning element and much more appropriate to run inside. Still need venting but not like running the stove.

Shoot! Hate that you can't fix a typo in the title of the thread.

Same thing happened with our new camper the first time we tried to use the furnace. Turns out we had the fan switch on the thermostat turned to the wrong position. No where in any manual told us that. I called the dealer and they told me. Flipped the switch and walla.......heat!!

[Ke5rbd]

Have the fuel pressure out of the regulator checked. I had one do nearly the same thing. It would run fine when not real cold, but would light and go out about 3 times in few seconds then shut off the burner altogether. The propane tank pressure gets lower when it gets cold and I suspect the regulator output was low also. I put new regulator on and no more problem. There is also a high flow detector built into the regulator that will shut the propane off that could cause it. It is there in case a line breaks to cut the propane off. Had one of these go bad also, but it is built into the regulator I think. Any reputable RV repair can check the regulator. Some regulators are adjustable, but need a gauge to check it. Don't think the high flow detector is serviceable. After Fixing the regulator the Hot Water heater when on propane could be heard running as it should. It would occasionally not light also and would have to cycle it. I had electric and gas water heater so didn't think too much about it. The Water heater generally sounds like a jet engine running.

[wmtire]

Low propane in a cylinder can also be a cause, especially if your other cylinder isn't open (assuming you have 2) or your auto changeover hasn't occurred yet. You stove may still work with the low propane, but the gas hog furnace won't. A Suburban furnace has to have a minimum of 11" W.C. line pressure.

I just ran into this Saturday with a friends camper. He asked me over to help him figure it out why his furnace would not get hot (fan was running). He had his spare propane cylinder turned off so the auto changeover could not occur.......but his stove still worked with the low cylinder that he had. I opened his spare cylinder valve, manually flipped the changeover to that cylinder and Presto, the furnace started working again.