Help - Scamp furnace problem

[Ttocs M]

My furnace on 2005 Scamp 13 deluxe (Suburban brand) has a lighting problem. It won't light unless one goes outside and covers the air vent, then it will light. The pezio lighter strikes 3 times then goes off, never to be heard from again.

Seems to be an airflow problem? Scamp is at the trailer repair shop, and they are having same problem. Once it lights, will relight with no problem. But if furnace is off for any length of time (e.g. 1 day), won't relight unless one goes outside and closes off air intake vent with your hand.

Instruction manual that came with trailer is for Suburban furnaces NT-12SEm 16SEm 20SE...not sure which one is mine. New thermostat was installed and works fine.

Has anyone experienced this and solved problem?
Thanks.

[stevebaz]

I would have the propane pressure and flow checked at the fridge. Closing off the access to free air would have the effect of raising the fuel density in the air to fuel ratio. Unless opening the hatch door relieves a short in the system. Is this an issue by its self or does this happen when other propane appliances are operating at the same time. Make sure you have proper propane flow and pressure when all appliances are operation.

Could be an issue with low voltage at the fan motor not spinning the fan fast enough or a sticky sail fan switch. Both cases the igniter will try and start but will shut off if there is a no light issue.

The igniter working and then not working is because it is doing what its supposed to do. System senses a no light situation and shuts off. If you immediately turn off the heater and turn it back on again I expect the ignition will attempt a relight.

Was there a recent parts change in the propane system?

[Bob in Mb]

Sounds like air in the propane line- make sure that all propane appliances are turned fully off before turning off the valve at the tank , when shutting down. If this does not help you may have a leak in the supply line somewhere . With this type of furnace it is always a problem to light when a new tank is installed , until all the air locks are gone. I believe that the furnace should retry after a set amount of time , I do not remember how long it is but 3 minutes rings a bell .

[floyd]

I think the sail switch is sticking or there is an obstruction in the vents.

[Carol H]

Propane regulator? Not enough pressure? You might try lighting all three burners on your stove to see if the flame is all blue, if you see yellow it could possible be a propane pressure issue.