Gas Furnace at altitude

[duluthdan]

Interesting experience with the gas furnace in my WF 1790. A couple days ago my dog and I camped at 8,920’ in the Rocky Mountains and the furnace would not light. So we spent a rather chilly 37 degree night. I wore my stocking cap and broke out the 20 degree sleeping bag. Next day we get home to 6,490’ altitude and the furnace lit and produced heat. Going over my travel log the next highest elevation that the furnace worked at without issue was at 8,546’ elevation with temps in the low 40s.

So seems like I will not be camping, on purpose over 8,600’.

I can get a small space heater for use at sites with power, but there are often times we are out in the sticks without shore power and in these mountains it gets cold at night even in the summer.

Any easy fixes?

[BobC]

I didn't read through them but if you Google "RV furnace high altitude" you'll come up with a lot of hits. You're not alone so I'm sure there's an answer out there. Here's an example:

https://www.granddesignowners.com/fo...hp/t-8029.html

[Mike Owens]

So here's the deal. Thinner air is causing your issue. It is jetted for normal altitude and that would be considered high altitude. The jets or orifice needs to be smaller and here is why. The spark ignitor requires an air fuel mixture close to normal burning. The lower oxygen content at altitude makes the burner / pilot way too rich for combustion so it doesn't light. Propane systems (because of the heaviness of the fuel) have a lockout safety that will try and light a few times (the electronics vary depending on manufacturer for amount of retries) then require resetting to try and light again.