Furnace won't keep running

[LJ-TJ]

Hey gang just getting ready to head out on the road and tried the propane furnace. She fires up all right but after about 10 sec she goes out. Stove seems to work fine, anybody got any thoughts what might be the problem. Thanks

[OldEdBrady]

Just a possibility; some kinda blockage in the gas line to the furnace.

Mine will start when there is no propane in the line, but shut down after a few seconds or so.  Happens to me when I forget to turn on the valves.

[Froggy1936]

Need more info ,is the fan running ?  If the fan does not come on (bad, or Dauber nest stopping it from turning Exaust blocked etc) Safety switch will shut it off.  Did furnace from the old rig survive the fire ?  Frank

[DaveVA78Chieftain]

Is it a pilot or or DSI model furnace?  Different possibilities.
Have you looked here for the answer? http://www.classicwinnebagos.com/forum/index.php?topic=2640.0

Dave

[ibdilbert01]

We had a simular issue with mine when we first fired her up, she would run for a very short time and stop.   As frank said, check for Canadian mud daubesr.   W%

[polarman]

 Not meaning to hijack the topic, but my furnace runs, pilot stays lit, and fan blows, but it wont throw a flame and heat. It's a Coleman in my 73 Brave. All of the connections look good and clean. Is there anything I can check myself? I know jack about furnaces. I have guests staying in it at the end of the month and it will be cold. I have no money to pay someone to look at it either.
At least the electric baseboard heater works.

[DaveVA78Chieftain]

Polarman,
Have you looked here for the help? http://www.classicwinnebagos.com/forum/index.php?topic=2640.0

Could be a blockage not allowing enough air to flow such that the sail switch does not engage.
Could be a bad sail switch, limit switch, or gas valve.

Dave

[polarman]

 Yeah, I saw that. I was hoping that there is a way to test the components rather than throwing parts (=$) at it until I find the problem.

[DaveVA78Chieftain]

You measure voltages at different points in the circuit.  Reffering to the drawing below:
If the blower motor is working then you know the Thermostat is working and there is voltage to the blower relay.

The other path from the Thermostat goes to the Sail switch/Limit Switch/Gas Valve.
Connect black voltmeter lead to ground.
Turn furnace ON and measure voltage at junction between sail switch and limit switch.
12VDC at that point?
No - Bad sail switch or blower is not getting up to speed (blockage in air flow)
Yes - Move voltmeter red lead limit switch/gas valve junction.
12VDC at that point?
No - defective Limit switch
Yes - Defective gas valve or ground connection to gas valve missing.  If ground good then replace gas valve (if you can find one).

Dave

[polarman]

Thanks! I'll give it a try in the next week or two. I should make sure the batteries are up to snuff first.

[LJ-TJ]

Hey Guys sorry I've been absent but just got back from a trip. The old girl ran great. Apparently the furnace needs good voltage to run the furnace. My voltage drops to 10 volt so in the morning I'm going to take a fully charged battery and connect it directly to the furnace by passing the inverter and see what happens.  Hm?

[polarman]

 Good luck!

[DaveVA78Chieftain]

BTW - I just helped a poor guy with his wife out in Colorodo cold using this technique fix a short in his Suburban NT-24M (not to be confused with a NT-24SP model) so it does work.  His fan switch was shorting out to the burner tube blowing the fuse because the weight of the fridge was bearing down on the furnace.  He did have a DSI model though.  You never know what the issue is but a systematic approach will help you find the problem.  Understand the chain of events for your furnace then work the chain.

Dave

[jkilbert]

If the unit hasn't been used for a long time there is a good chance that the burner is rusted. it is either cast iron or stamped steel. take it apart and clean it well with a wire brush and blow it out...had this problem on mine and numerous times in dad's old rv. also because the burner chamber vents outside you may have wasp nests that you cant see until you get it completely apart.

[tiinytina]

ours had mud dauber nests all the way in the back of the unit.. and removing it for a thorough cleaning meant removing the entire kitchen... but cleaned and screen now over inlet/outlet no problems since...

tina

[LJ-TJ]

Well things aren't looking good. I've done all I can think of but can't seem to keep the furnace going. The best I could do is about two minutes. I've torn the hole thing apart and the thing is like new. Still doesn't work. Apparently parts are no longer available.Soooooo looks like a new furnace is in the works. What I'd like to do is pick your brains on what might be a good furnace to use as a replacement. Most importantly I don't want to cut another hole in the side of my New 1975 Winnie, I'd like to be able to use the same exhaust hole. Any Thoughts.  Hm? Thanks Guys.

[salplmb]

if my heater went out i think i would go with the hydronic heat. there is a good thread going on it already. it really is way more efficient and more contolable heat, i am a plumbing contrator so i may be a little bias. but all the claims r true. also the space that the heater was in can now b used for storage.
just a thought.
sal

[JDxeper]

TJ
Ran across these heaters FYI

http://www.eheat.com/products/Envi-High%252dEfficiency-Whole-Room-Plug%252dIn-Electric-Panel-Heater-%28HH1012T%29.html

JD

[Oz]

TJ?  Anything new with this?