Furnace won't ignite

Dirty sail switch.
Are you connected to shore power or using batteries/
If shore power it could be dirty. Locate the sail switch and use canned air to blow out area. Or if you have access to air compressor blow out the whole compartment.
If running on batteries, the voltage maybe low enough to prevent sufficient air volumne to operate the sail switch.
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you need to give the furnace model, I am not sure Dometic as a brand even has a furnace, they have heat pumps …

UPDATE


This was using shore power.

As to make and model, not sure and paperwork is with the trailer at the storage lot.

Thanks for the help, and where is the "sail switch"????

Bisker wrote:
UPDATE


This was using shore power.

As to make and model, not sure and paperwork is with the trailer at the storage lot.

Thanks for the help, and where is the "sail switch"????

It is a sail like leaver that is lifted by the air movement when the fan speed is at a sufficient speed causing a switch to close… but other things can cause your problem like blocked air flow…

click

Thanks for the link, looks like I checked everything I could. Hopefully the services tech will make easy work of it, TT is new so warranty should cover any work needed.

First let me say that I worked with my father when I was a teenager, and learned quite a bit about furnaces. He was a serviceman for a gas company. My experience with him gives me confidence to delve into this type of problem, but if you do not have such experience, then it's best left to professionals.

I had the same symptoms with my furnace, so I removed it from it's undercounter location and disassembled it. I found that a small insect(probably a spider) had plugged the orifice which feeds the gas into the burner venturi. At least it was plugged enough to limit the gas flow which prevented the ignition of the burner. All else was normal, spark, valve, etc. After cleaning the orifice (jet) or spud as my dad used to call it, it worked fine.

I found a solution to this recurring problem by placing a fine screen over the vent through to the outside of the camper. This has prevented insects from entering the burner from the outside, and I haven't had any trouble since.

I'm not recommending anyone do this repair. Only those with experience with gas appliances. Care must be taken to ensure no leaks after reassembly.

sail switch have had the same issue before

I once removed a furnace and dumped a whole coffee can full of mud dauber nests out of it. The Screen is a very good idea on any furnace. They should be installed by the manufacture.

The screens are a very good idea. When we bought our Puma used it had the screens already installed.

On our Crossroads TT in order for the furnace to kick on, the fan must be set to "auto" (not "hi" or "low"). Try that and see if it comes on.