Ruly

Had this problem in our Sunrader a couple of years ago. Turned the thermostat up, the furnace blower would come on but no heat. Turned out it was my coach battery not supplying enough juice. This was causing the blower to not blow hard enough to trigger the sail switch in the furnace. The sail switch is a safety feature that will keep the furnace from lighting if the blower is not working (or in my case not working strong enough). The tell tale sign that let me figure it out was that the furnace would light when the RV was plugged into electricity (furnace blower gets power from transformer instead, which is now enough to trip the sail switch). Try your furnace after plugging in, if it works either charge your battery or replace it.

Does anyone know the difference between a Suburban NT-12SE furnace and a NT-12LE? What is the significance of the "L" versus the "S"? Both are 12,000 BTU direct vent. Is the NT-12LE a suitable replacement for the NT-12SE or is there a compatibility problem with the different model numbers? Thanks in advance for any info.