Newbie checks in; furnace issues NT34SP

[jayman729]

Hi all... just purchased a 1988 Winnebago Elandan. As you would expect, a 22 year old RV that has been sitting for 2 years has a few issues! It only has 29,600 original miles and runs and drives well. A few broken latches on cabinets, pitted bathroom fixtures, faded carpet that needs replacing and a dead mouse under cabinet were the first observations. After hooking up to juice and charging batteries, I attempted to run the furnace; Suburban NT 34SP. Purged gas line and checked voltages. Burner ignites and runs for 2 minutes and then flames out....propane tank gauge shows 1/2 full, so I'm assuming control module may be bad....any one out there have experience with troubleshooting this model furnace?

[BlueLine]

Don't be too quick to think control module, though it very well could be. I had burner problems also, but mine turned out to be bugs (Mud Daubers)http://www.irv2.com/attachments/phot...auber_SF42.jpg.
Any thing that restricts airflow to or from the burner chamber will adversely affect the heater's performance. Check the units intake and exhaust ports, and also inside the RV's system ducting. Closed or restricted registers, rodent nests in the heat ducting and restrictions in the return air. Are you sure the burner is igniting? When you turn the unit to heat and set the thermostat you should hear the blower come on in the furnace, after in runs for a minute or so you should hear the rumble of the burner being ignited and feel heat almost instantly. If the burner doesn't ignite the unit will shut down (About 2 minutes) You can also check the outside exhaust port, you should feel heat there if the burner has lit. By the sounds of it, dead mmouse etc. check for restrictions, I had Mud daubers nests in the Burner chamber, in the exhaust pipe, intake pipe and in the rotary fan wheel on the furnace.
There are several posts dealing with your unit, If you go to the top right portion of your irv2 web page and type in Suburban Heater in the Google search box and enter, you'll get all the past posts dealing with various problems and solutions others have had or done.
I have also replaced carpet with a lamanent, trips to sandy and red clay areas prompted me to make a change away from carpet very quickly.
Welcome to the forum JayMan729, you'll find that irv2.com will be one of your greatest tools to use in dealing with your problems.

[KIX]

There will be some method of sensing a flame is present which will allow the gas valve to continue supplying propane to the burner. I am guessing that this flame sensor is not reporting back to the gas valve. If you have electric spark ignition the point where the spark originates at the burner is probably the sensor also. Hope this helps you.

[RVhauler]

need 12 volts to insure the fan is up to speed. If fan is not up to sppeed then prevents ignition. Suggest cleaning burner area as well as checking previous suggestions