NT-22 or 30

[Phaedrus]

This model furnace made by Suburban has fried the hair off my arm when I tried to light it through the cap, it acts as though the core is going to light then...WHOOOSH fire out the front of the furnace. This sucks. I'm asking Santa for an Air-Elf to get me through this problem, unless you folks have any ideas.

[Pick]

Ahhhhh, make sure the thermostat is in the off position. Hold the button in, light the pilot. Let the pilot warm the thermocouple for 30 seconds or more, then let go of the button. Put the cap on. THEN turn the T-Stat up.

[Phaedrus]

I was hoping for such a simple solution. I still have the same problem. The pilot seems to struggle to stay lit and then goes out immediately after I let out the reset button. The whole time I am holding in the reset button, it seems as though the flame wants to "jump" out the pilot hole.

[Pick]

Ok, now try lighting the furnace with all the doors, vents and windows closed. With a door or window open, wind will blow through furnace causing the condition you are seeing.

DON'T LET A BUNCH OF PROPANE BUILD UP WHEN DOING THIS!!!

If it does not light right away air things out.

[Phaedrus]

Tried that too. At one point the thermocouple/pilot got so warm it automatically kicked the blower on. But once again it just will look like it's going to light (nice blue flame en-circling the thermo-couple then next thing you no the flame shoots out My arm is going to soon be as bald as my head

[thenewkid64]

Are you sure the gas pressure in the LP system is at the right pressure? It sounds like you may have a low pressure problem 11-14 inches of WC pressure is what you should have.

Also something to check is the gas level in the tank, low levels of gas will sometimes make a high use device act odd.

[Phaedrus]

I've checked everything I can think of, Time for me to check myself into a "facility"

[Pick]

If your blower is kicking on then your thermostat is NOT in the off position!!! You may have a defective thermostat.

At this point, it may be wise to take it to an RV dealer.

Are the flames shooting out of the hole from the pilot or main burner????

[3Ms75Argosy]

I was thinking the same thing. The blower shouldn't be turning on when the thermostat is on off. I think somehow, the thermostat is "on", and you are lighting not only the pilot but also the main burner at the same time! However, I also believe the thermocoupler shouldn't be letting the main burner go on if the pilot is not lit.

Sounds like service time. The 100 bucks or so is a lot cheaper then a skin graft on your arm.

P.S. - I suppose you could roast marshmellows inside the trailer with that flame!
Marc

[thenewkid64]

I concur that the blower should not be starting. The main burner will light due to the themostat too. If the thermocoule is hot enough then it will allow the gas valve to open, period. It does not sense the blower, or the fact that your fingers or arm are in proximity to the "flame thrower"

If the thermostat is off the funace should follow this sort of order when heat is called for.This assumes the pilot is lit and staying lit.

Call for heat

Spin up blower, at 75% of speed it should activate the sail switch that feeds 12 V to the gas valve.

Electronic gas valve opens, gas will not make it to the burner if the thermocouple has not been heated due to the safety valve, and pilot ignites gas.

Internal bi-metal temp switch senses heat and allows furnace to continue to run. If no heat is sensed then furnace goes into lockout and thermostat must be reset to remedy the lockout.


There are really 10-12 steps, but I distilled them down for this example. The trouble shooting is straightforward, but if LP gas scares you, HAVE A PROFESSIONAL DO IT! The $100 is cheap compared to the personal loss that could occur.