New diesel furnace exhaust smell

Greetings-

Last week I had my Espar D8LC serviced and a new exhaust run to the external hull fitting. This included new inside sleeve and thick external insulation padding. After a few minutes of running I noticed a sweet smell from the area and some whispy smoke. The smoke has gone away but the installer tells me that i just need to run the heater to "cook" oils off and cure the new insulation. I was told about 2-4 hours of runtime.

I ran the heater normally (cycling on and off regularly) for a day or so but smell remained and when I used a FLIR to check temps I found that up at the gooseneck I'm reading over 250*F right as the gooseneck just touches the deck. I would like them to come back, reorient the exhaust to create an air gap and potential even install some insulation matting to the underside of my fiberglass decking to protect it. Finally, I do believe that to tighten the thu hull they did clock it clockwise a tiny bit which change the angle upward ever so slightly.

So questions...

1. Is 250*F too hot for fiberglass hull? I think so and some (all?) of the smell may be resin?

2. Has anyone had to cook off the smells from a new furnace installation? If so, how long did it take?

3. I was not expecting such high temps off the espar. Over 400*F right at the egress of the combustion chamber and over 250*F 6 ft away at the top of the gooseneck. Any further recommendations for a really hot exhaust for an Espar forced hot air diesel furnace?

Pictures to show before and after inside the closet against the hull.

Thanks in advance!

-tozz

I have no experience with those units, but that temperature at the elbow would concern me also. If nothing else, I would consider mounting the elbow on a larger diameter plate for greater separation from the fiberglass. Also would like to see the elbow completely covered by the insulation padding.

Ted

I installed a new Hurricane heater recently and the first few hours of operation were smelly. The flexible exhaust tubing is quite oily when new. I'd bet you're smelling the cook off of those oils.

Jeff F said:

I installed a new Hurricane heater recently and the first few hours of operation were smelly. The flexible exhaust tubing is quite oily when new. I'd bet you're smelling the cook off of those oils.

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Thanks. I will look to mitigate the lack of air gap to try to remove the heat off the underside of the fiberglass deck and will fire it up for a few more hours. Someone told me that because the espar's run so hot they have to use the highest grade of heat retardant blanket. More smell, longer time required to cook it off.

-tozz

Next time you fire it up, shoot the outside hull where that elbow is and see what the temp is? Just curious.

w8n4sun said:

Next time you fire it up, shoot the outside hull where that elbow is and see what the temp is? Just curious.

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The outside? Swim on over and check for me. It's on my port side.

-tozz

Is that the double walled exhaust outlet made for these units? Doesn't look like it. The double wall fitting keeps the fiberglass relatively cool, and the exhaust pipe gets really hot. When I installed my Chinese diesel heater, I bought the Espar exhaust fitting. Cost about half what the heater did but you really need that. Mine had that smell for about ten minutes when first started but nothing after that. Like my house furnace does the first time it comes on in the fall, burns off the accumulated dust then no more smell. And with the good job you did insulating the pipe, the through hull fittings going to get even hotter.

tozz said:

Thanks. I will look to mitigate the lack of air gap to try to remove the heat off the underside of the fiberglass deck and will fire it up for a few more hours. Someone told me that because the espar's run so hot they have to use the highest grade of heat retardant blanket. More smell, longer time required to cook it off.

-tozz

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I'm my case the outside smell didn't last long, but I noticed it in the ER where the heater is for quite a while, weeks I think.

I can't comment on Espar. My unit is 50k btu with a 2" exhaust and a single woven cover I allowed at least 4" air gap with the ceiling of the ER, but it still gets very warm. I think I'll be adding a heavy wrap to mine. It's hotter than I was expecting

w8n4sun said:

Next time you fire it up, shoot the outside hull where that elbow is and see what the temp is? Just curious.

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FLIR pointing right up into the thru hull. ~400*F is the hottest I captured.

I wrapped my exhaust with a material from Amazon which is made for exhaust manifolds on race cars and such. It wasn't this exact item, but very similar:
https://www.amazon.com/dp/B0051UPJIC

Those exhaust hoses are downright scary. The soft cloth wrap that comes with them, or you can buy, does very little to reduce the danger to nearby wood or fiberglass.

On reason the elbow is hot is the insulation. It's holding the heat. Eventually the insulation is hot and just passing the heat down the tube. You'd be better off with an exposed pipe, held away from the hull and cabinets as much as possible and only insulated where needed. That way excessive exhaust heat contributes the heating the boat and the exhaust is much cooler by the time it reaches the hull.
The hull fitting I use has a larger pipe around the exhaust and exposes the center tube to outside air where it exits the hull. There's a bunch of styles and angles on ebay. See pix.

CaptTom said:

I wrapped my exhaust with a material from Amazon which is made for exhaust manifolds on race cars and such. It wasn't this exact item, but very similar:
https://www.amazon.com/dp/B0051UPJIC

Those exhaust hoses are downright scary. The soft cloth wrap that comes with them, or you can buy, does very little to reduce the danger to nearby wood or fiberglass.

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This is a great idea. Do you think placing this around the existing insulation blanket would work just as added piece of mind even all the way down the exhaust? I'm think of doing the whole length given the tight quarters and how little gap there is against the hull and inside the closet space.

Lepke said:

On reason the elbow is hot is the insulation. It's holding the heat. Eventually the insulation is hot and just passing the heat down the tube. You'd be better off with an exposed pipe, held away from the hull and cabinets as much as possible and only insulated where needed. That way excessive exhaust heat contributes the heating the boat and the exhaust is much cooler by the time it reaches the hull.
The hull fitting I use has a larger pipe around the exhaust and exposes the center tube to outside air where it exits the hull. There's a bunch of styles and angles on ebay. See pix.

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This is how the espar in the engine room is installed. There isn't a lot of room behind the closet but I'll check. Thanks!

250deg at the glass hull is pretty dam HOT. Have you ever seen fiberglass burning?

tozz said:

This is a great idea. Do you think placing this around the existing insulation blanket would work just as added piece of mind even all the way down the exhaust? I'm think of doing the whole length given the tight quarters and how little gap there is against the hull and inside the closet space.

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That's what I did. At one point I measured over 700F on the exhaust pipe, and it scared the crap out of me. I don't want any chance of that even getting near any wood or fiberglass!

I do agree that insulating better means higher temperatures farther down the pipe. I've never had the exhaust port at the hull on mine any more than warm to the touch. The flip side of this argument is that my exhaust hose is probably too long (although within spec) and the backpressure isn't helpful. These things are made to go in trucks where the exhaust would be very short, and only contact the metal frame, if anything.

The instructions regarding the exhaust pipe installation for my Webasto said; no more than 10 feet in length and no more than 270 degrees of bends. I also used a water trap at the hull outlet that keeps the fiberglass from getting too hot.

porman said:

The instructions regarding the exhaust pipe installation for my Webasto said; no more than 10 feet in length and no more than 270 degrees of bends.

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Yeah, mine said that too. But if I had it to do over again, I'd make the exhaust as short as possible. The fans (both combustion air and heated cabin air) are barely adequate and too much exhaust hose or duct work will cause it to overheat, and on the combustion side, to load up with carbon.

One way to reduce back pressure/length & bend problems is discharge into a larger pipe as close to the heater as practical.

My Espar stunk from the day I got it to the day I through it overboard. It was a battery killer too not to mention the soot. Never trusted it or it's installation. It defied all precautions applied to household furnaces.

I considered these heaters. There was a previous thread, I think largely about "Chinese" copies. One feature of the "originals" was exhaust and air intake were in one big tube, exhaust tube inside intake tube, so the latter cooled the former. Memory may be wrong, which explains why it has not been raised here, but fairly sure it was a smart feature of one brand.

BruceK said:

One feature of the "originals" was exhaust and air intake were in one big tube, exhaust tube inside intake tube, so the latter cooled the former. Memory may be wrong, which explains why it has not been raised here, but fairly sure it was a smart feature of one brand.

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Right, the ones I've seen the past few years all have separate intake and exhaust hoses. One coaxial hose would be ideal for marine use, but in trucks and RVs it probably doesn't make as much sense.

porman said:

The instructions regarding the exhaust pipe installation for my Webasto said; no more than 10 feet in length and no more than 270 degrees of bends. I also used a water trap at the hull outlet that keeps the fiberglass from getting too hot.

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I remember those numbers from Wabasto as I’ve installed two Wabys.
I suspect the temps are fine as the smaller dia inner pipe has an air jacket around it. The outside pipe of the air jacket contacts the FG hull. I was doubtful about it’s ability to keep the hull hole cool enough.

My present installation is 10’ long (max). I had no problems related to heat and my first Waby exhaust was only about 18” long.
If you don’t have an accessible Espar dealer call the Wabasto dealer (Sure Marine) in Seattle.

jgwinks said:

Is that the double walled exhaust outlet made for these units? Doesn't look like it. The double wall fitting keeps the fiberglass relatively cool, and the exhaust pipe gets really hot. When I installed my Chinese diesel heater, I bought the Espar exhaust fitting. Cost about half what the heater did but you really need that. Mine had that smell for about ten minutes when first started but nothing after that. Like my house furnace does the first time it comes on in the fall, burns off the accumulated dust then no more smell. And with the good job you did insulating the pipe, the through hull fittings going to get even hotter.

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It's not the double walled thru hull outlet. It's a generic that was installed during original build in '96-'97. I'll look into the espar fitting. Thanks!

-tozz

tozz said:

It's not the double walled thru hull outlet. It's a generic that was installed during original build in '96-'97. I'll look into the espar fitting. Thanks!

-tozz

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I no longer have an Espar.
I still do have the through hull fitting, which is on my list to remove and fill the hole.

My exhaust was not insulated and did not get hot enough to be of concern. It was not insulated, nor was it looped close to any interior bulkhead or to any exterior fibreglass.

I would be concerned that yours is too close to flammable materials, and likely too hot. That heat is also exacerbated by the insulation, but in your installation, you likely, due to its close proximity to an interior locker, have no option to remove it, so need to at the very least, re-aim it and possibly deal with the through hull.

koliver said:

I no longer have an Espar.
I still do have the through hull fitting, which is on my list to remove and fill the hole.

My exhaust was not insulated and did not get hot enough to be of concern. It was not insulated, nor was it looped close to any interior bulkhead or to any exterior fibreglass.

I would be concerned that yours is too close to flammable materials, and likely too hot. That heat is also exacerbated by the insulation, but in your installation, you likely, due to its close proximity to an interior locker, have no option to remove it, so need to at the very least, re-aim it and possibly deal with the through hull.

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Yeah, I'll be working on a solution over the next week or so. The crazy part is that this is basically the same design and route that the previous exhaust took and worked for 25 years. The changes to the design when we replaced the exhaust were minor but seem to be significant enough. It's just a matter of making some small incremental changes to get the radiant temps down a bit.

-tozz

Poor installation. Get rid of that last 180 bend before it goes ito that 90* fitting and run it straight, the most efficient way to run an exhaust. Use the fitting as pictured in Lepke's post.

I disagree with removing the insulation, you want the heat overboard, not cooking those other lines and systems. Get a "proper" exhaust fitting and make them insulate the entire run.

You could enclose the entire exhaust in a larger insulated pipe and run air around it if you want to recover the heat, but you run a risk with exhaust contamination if it runs to an area where you breathe.

Or wrap a copper coil around it and run water through it for some extra heat in a water tank or...?

tozz said:

It's not the double walled thru hull outlet. It's a generic that was installed during original build in '96-'97. I'll look into the espar fitting. Thanks!

-tozz

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I got mine on eBay, I think it was this one:
https://www.ebay.com/itm/24MM-316L-...571364?hash=item1cb7abc2e4:g:fKkAAOSwlUhbhuz1

The center part gets pretty hot, but the outer wall and flange are just touchable warm. Nothing hot touches the fiberglass. The gasket is silicone and good to 400F.

Xsbank said:

Poor installation. Get rid of that last 180 bend before it goes ito that 90* fitting and run it straight, the most efficient way to run an exhaust. Use the fitting as pictured in Lepke's post.

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Yeah, i'm leaning towards redoing it but myself so I know it's done right. Cut down the flexible exhaust a little, reinstall the thru hull with one with the double skin and remove that goose neck a bit. But someone told me the gooseneck was for water intrusion since that thru hull is exposed on the bow and in heavier seas it will get exposed to wave action.

-tozz

https://www.amazon.com/Eberspacher-...st+fitting&qid=1613335874&s=automotive&sr=1-7

Tozz, You need a gooseneck to prevent a glug of water from running into the heater. I killed one that way. Be careful of unintended consequences.

Getting back to your original questions, I'd bet the temperatures have always been as high as you describe, assuming the new exhaust mimics the old. It was only the smell from the new hose that drew attention to the system.

Is it a concern? If it were me I'd look carefully for signs of heat damage in the under deck area and around the hull fitting. If I didn't find any I'd add it to my project list, but it wouldn't be at the top.

Jeff F said:

Tozz, You need a gooseneck to prevent a glug of water from running into the heater. I killed one that way. Be careful of unintended consequences.

Getting back to your original questions, I'd bet the temperatures have always been as high as you describe, assuming the new exhaust mimics the old. It was only the smell from the new hose that drew attention to the system.

Is it a concern? If it were me I'd look carefully for signs of heat damage in the under deck area and around the hull fitting. If I didn't find any I'd add it to my project list, but it wouldn't be at the top.

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Agree on the gooseneck. Any modifications would be to bring it back closer to the original design and nothing more.

I have thought your second point and perhaps about this being somewhat of a red herring considering how close the two installs really are. The temps probably aren't _that_ much off form original but it's still unnerving to see those temps so close to the inner wall of a cedar closet and the hull itself. My perspective is once access to the hull has been exposed, I should try to make it an even better solution and reduce the heat where we can for piece of mind moving forward.

Seems like there's just enough of a difference to drive the heat up a bit especially with the loss of the air gap against the underside of the sidedeck. Once that's addressed and I get some lower readings on the FLIR i'll button it back up and move on to the other projects.

thanks!
-tozz