Furnace duct questions for my diesel heater

[StillCamping]

Hello, I have just finished up my diesel heater install. I have tapped into the furnace duct that dumps into the storage bay. My questions is, how hot is too hot for the ducting? I haven’t gotten a surface temp yet but it is hot to the touch. I’ll include some pics to better explain what I’ve got going on.

This is the front storage compartment where the heater is mounted.


This is the duct I added to feed the factory duct


Just another angle showing the factory duct a little better


The ducting I have shown in the pics gets uncomfortably warm to the touch when the heater is running. I can smell “hot” inside which is what made me nervous in the first place but our furnace hasn’t been run yet this season and I know there’s gonna be some burn off when first fired up.

Figured I’d throw the questions out there. If your not familiar with diesel heaters then this won’t make any sense to you but I know at least one other member has installed one.

[Paul & Deb]

So are you using this as an adjunct source of heat or completely bypassing the factory furnace?

[StillCamping]

The furnace is an absolute last resort. Too expensive, too much moisture. The end goal is to run two of these and not have to use the furnace at all, but still have it fully functional if needed.

I got ahold of a infrared thermometer (can’t find mine) and the actual temp doesn’t go up past 165° At the outlet and a consistent 140°ish at the vents, so I should be good to go. Seemed like a lot hotter than that.

[jkwilson]

The furnace is an absolute last resort. Too expensive, too much moisture. The end goal is to run two of these and not have to use the furnace at all, but still have it fully functional if needed.

I got ahold of a infrared thermometer (can’t find mine) and the actual temp doesn’t go up past 165° At the outlet and a consistent 140°ish at the vents, so I should be good to go. Seemed like a lot hotter than that.

Your furnace will not create any moisture inside the living space unless something is seriously wrong with it. You’d have a CO alarm sounding if it was producing any moisture in the living space at all.

[StillCamping]

Learn something new everyday. I guess I must have mixed up my research years ago with the un-vented propane furnaces. my mistake!

[jkwilson]

Learn something new everyday. I guess I must have mixed up my research years ago with the un-vented propane furnaces. my mistake!

I burn one in my shop when it’s really cold. Made it rain a couple of times

[boyscout]

Your furnace will not create any moisture inside the living space unless something is seriously wrong with it. You’d have a CO alarm sounding if it was producing any moisture in the living space at all.

Hmmm. When our trailer is REALLY cold, freezing cold, and we turn on the furnace a WHOLE lot of moisture accumulates on its interior surfaces. It's not obvious for long - dries up in less than an hour - and doesn't appear except under those freezing-cold-startup conditions. We've never had an alarm.

Are you saying that we have a problem? What is the problem?

Thanks.

[jkwilson]

K

Hmmm. When our trailer is REALLY cold, freezing cold, and we turn on the furnace a WHOLE lot of moisture accumulates on its interior surfaces. It's not obvious for long - dries up in less than an hour - and doesn't appear except under those freezing-cold-startup conditions. We've never had an alarm.

Are you saying that we have a problem? What is the problem?

Thanks.

For the furnace to generate moisture in the trailer you’d have to have a combustion chamber leak. What’s likely happening is that the warmer air holds more water and picks it up from the inside. As that warmer air contacts the cold surfaces, you get condensation. Once the heat warms the interior surfaces, the moisture will go back into the air.

[Second Chance]

K

For the furnace to generate moisture in the trailer you’d have to have a combustion chamber leak. What’s likely happening is that the warmer air holds more water and picks it up from the inside. As that warmer air contacts the cold surfaces, you get condensation. Once the heat warms the interior surfaces, the moisture will go back into the air.

This^^.

Rob

[boyscout]

K

For the furnace to generate moisture in the trailer you’d have to have a combustion chamber leak. What’s likely happening is that the warmer air holds more water and picks it up from the inside. As that warmer air contacts the cold surfaces, you get condensation. Once the heat warms the interior surfaces, the moisture will go back into the air.

So do we have a combustion chamber leak? Or (as I believed) moisture already in the trailer and its air being carried by warmer air currents created by the furnace onto still-very-cold surfaces where it condenses.