The saga continues...
Backstory: [Me: 2019 Hawk-super clean] I was trying to get the furnace to light at 8,000 ft and 9,500 ft elevation. It would spin up for about 15 seconds and then shut off. Plenty of battery juice.
Drat!
Back home I took unit outside cover off and checked sail switch with for debris/dust/gunk, it was pristine, put back in carefully.* Back home at 5,300 ft in my driveway the furnace works perfectly, starts right up, zero issues.
*Obviously you gotta check to see if your entire unit is fouled with debris/dust/gunk—and don't forget the thermostat, which can get multitudes of spider eggs, food and whatnot into it. Or bad battery (mine doesn't have one).
Update. I spoke to Stan and one of the techs at FWC. They are telling me that Dometic (all most all other) propane furnaces cannot function above a certain altitude.
Huh?
"So, the high elevation limitation is that the air is thinner and the fan only runs at one speed. That fan has to push the sail of the sail switch over to activate the firing order of the furnace. If the air volume isn’t capable of doing that, the furnace definitely will not light. This also tells the furnace that the air/fuel ratio is too low(low air/high fuel). If lit, it would cause a rich mixture possibly causing a weak flame and/or high CO levels. These are safety devices that prevent accidents. This is not limited to Atwood/Dometic products. These are safety devices found in every furnace that is legally sold/installed as OEM equipment in the United States.
[response to me telling him I cycled power a bunch times using the thermostat trying to get it to start] Also, by turning the unit off and then back on again in succession, could trigger the safety lockout feature(breaker) that’s located behind the outside furnace door.
There are workarounds to furnaces that do work at higher elevations but, Four Wheel Campers cannot install them due to restrictions and liability limitations. Espar Diesel heaters are phenomenal and work very well in almost all elevations but, they can only be added as an aftermarket item by a distributor/installer. I believe Rocky Mountain FWC installs them in some camper models. Propex/Heatsource HS2000 is a great propane model that works good too, and is very popular in Europe but again, is not certified for OEM manufacturers to install here in the US. I can personally understand the frustration, as I too have been in the same situation with that brand of furnace in many different makes of campers and travel trailers besides FWC products."
Fair enough, I understand the science/safety and legal limitations. I was ignorant about the entire high-altitude issue. Color me city boi again!
And the last couple of days I've read about a zillion blogs and forums about the subject. I'd LOVE to get a Propex/Heatsource HS2000 installed, but finding a certified shop to do it is going to be tough. (Anyone got any leads? I'm in Utah but I can road trip to get it done. Road Trips are fun!
)
From my reading, I've found a few ideas I'll pass along (one untested and possibly very dangerous):
- Turning on the gas at the tank too fast is really bad because it messes with all kinds of delicate, pressure sensitive and thus pressure-regulating do-dads in the connections to the system. And some devices have their own pressure sensitive and thus pressure regulating do-dads in the connections into their units. (I only have stove and water heater on propane, no propane frig). A weak and/or stuttery stove flame is one sign that you opened the tank to fast and engaged a pressure-regulating safety feature. See next item to fix.
- You can get all kinds of strange things happening with your connection/hose/delivery line. Some ppl swear that if you're having problems with your propane appliances to turn everything off including tank, unscrew the main tank connection let it calm down unhooked, wait a few minutes, retook the tank up and sloooowwwly turn the tank back on. One dude said he also may slightly unscrew the tank connection while it's hooked up, but only ever so slightly as to relieve weird back-pressure and only for a second or two before he re-tightens the tank connection. No smoking!
- Some ppl mess with the pressure regulating items coming out of the tank. This sounds way dangerous to me and I'm definitely going to get a RV shop pro to mess with anything like that.
- Some ppl get furnace air intake "high altitude" replacement parts that increase the air into the unit to help it burn at high altitude. This by far seems to be the best idea for long-term, high altitude furnace use. I'm on the hunt for this "kit" if it exists.
- Some people bring the "Little Buddy" or similar ceramic portable heaters and use those inside. These are the rigs on fire or with dead people inside because of poisonous gasses. Kidding! You gotta vent these and they make a ton of moisture and use a bunch of little propane tanks. Vent open=cold. But in a pinch it would get my Westie out from under the covers and my wife out of the truck cab. And they are $80.
Please, anyone wanting to add to or correct any of this malarky post it or PM me and I'll fix my info.
Sorry for the epic post, too much coffee!
