50 replies to this topic

[Jack]

Looks like we have been lucky, but we have camped at 8500' without furnace problems - but the duct hose in our Fleet is offset by only about an inch or so.

 

Taping two vent slots allows us to direct the heat at our feet which provides nice warmth in the front dinette. At night we direct the air flow up to the bed, which makes for a noticeably warmer sleeping area.

 

Edited by Jack, 09 March 2021 - 08:27 PM.

[Dphillip]

The furnace in our 2015 Hawk has always been unreliable, sometimes working flawlessly and sometimes failing to turn on leaving us cold and miserable during the night. I preformed  the aluminum foil duct tube adjustment many members have suggested and actually cut and removed approximately 6 inches of excess duct tube. I’m pleased to report that after a 10 day trip to Moab where we had some chilly nights and mornings our furnace worked perfectly and never failed to light. It’s amazing how something so aggravating can have a simple and cost free solution. Thanks to all who suggested this!

[Charlie]

Man, I just can’t understand why the foil hose could have any connection with the furnace not starting. The flame/exhaust side of the furnace HAS to be completely isolated from the warm air side, otherwise you would be asphyxiating your self. But I can’t argue with the reported evidence. Maybe someone can explain why this fix works?

[patrkbukly]

Man, I just can’t understand why the foil hose could have any connection with the furnace not starting. The flame/exhaust side of the furnace HAS to be completely isolated from the warm air side, otherwise you would be asphyxiating your self. But I can’t argue with the reported evidence. Maybe someone can explain why this fix works?

I am right with you here. I would like to understand that myself.

[larryqp]

I was recently camped in the Springs Mts outside Las Vegas, in my 2019 hawk, not sure of altitude but probably over 7000 ft. When the temperature dropped, I turned on the furnace. It cycled but did not spark. I moved the thermostat switch to off and back on, it cycled but didn't spark, then cycled off. I left it set at 50 degrees, it was about 30 degrees outside. In the middle of the night I woke up to a warm camper, the furnace ran fine in the morning. This is the second time I have had intermittent problems. I suspect the sail switch is sticking and then after a number of cycles it unsticks.

 

So I'm wondering if some sort of lubricate on the sail switch might help. My concern would be the lubricate attracting dust and therefore making the switch stick more.

Any thoughts?

[Dphillip]

I’m certainly no expert when it comes to the camper furnace but here is what I’ve experienced.

When my furnace would cycle and not light I referred to the WW forum and the 4WC facebook page. I learned about removing and cleaning the sail switch. I carefully removed mine and found there is not much to it. Just a small inexpensive switch housed in a metal enclosure with a little tab sticking out that acts as the sail. When the furnace fan kicks on the wind from the fan flips the tab and throws the switch. My switch was very clean and there is no way to lubricant or modify the switch. 

When this didn’t correct my intermittent furnace problem I tried re-routing the foil duct tube. I had read that if there is any restriction in the foil tube the wind generated by the furnace fan will not exit the furnace properly and will prevent the sail switch from tripping. I was skeptical but gave it a try and removed about 6 inches of foil duct. This to my surprise solved my problem.

[patrkbukly]

I’m certainly no expert when it comes to the camper furnace but here is what I’ve experienced.

When my furnace would cycle and not light I referred to the WW forum and the 4WC facebook page. I learned about removing and cleaning the sail switch. I carefully removed mine and found there is not much to it. Just a small inexpensive switch housed in a metal enclosure with a little tab sticking out that acts as the sail. When the furnace fan kicks on the wind from the fan flips the tab and throws the switch. My switch was very clean and there is no way to lubricant or modify the switch. 

When this didn’t correct my intermittent furnace problem I tried re-routing the foil duct tube. I had read that if there is any restriction in the foil tube the wind generated by the furnace fan will not exit the furnace properly and will prevent the sail switch from tripping. I was skeptical but gave it a try and removed about 6 inches of foil duct. This to my surprise solved my problem.

Thats good enough of an explanation for me.

thank you for that.

[grandby49]

Has anyone tried bending the sail switch to catch more air?

[Yonder37]

Just want to add another vote for removing the foil duct.

 

Got a 2023 Hawk earlier this year. Had never used the furnace, beyond testing it once or twice at home.

 

Was camping at 4,100 feet on Thanksgiving Day and it was cold. Switched furnace on, got fan immediately, but no ignition, just clicking sounds and cold air.

 

Then remembered reading in this forum about the foil duct. Tried removing the whole front grill, including the foil duct. Boom -- hot air.

 

Put the front grill back without the foil duct. Still worked. Thanks !

[Charlie]

I’ve certainly become a believer. I removed the tube, and have had several years of flawless operation. I think altitude dependence is a red herring. I’m convinced that the corrugated ducting just creates enough drag to slow down the air so that there is not enough airflow to activate the sail switch. Maybe a smoother or shorter tube would help. Since it seems to be a marginal effect, units with healthier blower motors won’t see the problem. And really, I don’t think the removal affects the performance at all.

 

Lucky that you remembered this thread!