Foam inside a/c ducts

stephens013

stephens013

Active Member
Oct 8, 2009
756
Ft Walton Beach, Fl
Boat Info
2001 510 Sundancer
1997 400DA Sundancer
1994 Chaparel 310 Signature
Engines
3196 Cat; 660 PHP
3116 Cat; 340 PHP
resently I have been having old foam insulation on the floor of my boat. It's little chunks of foam that is on inside the over head duct work. Not like it's a black snow storm when the fans are on but go away for a day or two and it's a mess. Not sure how to stop this little problem. Was thinking about taking off the circular defuser on the ceiling where the ac duck/peplum dumps in to the salon; scrap and vacume as much of the old hardened foam as possible; then coating as far back as I can with spray adhesive. Just can't see how the ceiling defuser/vent comes dislodged from the ceiling.
Anybody run into this sort of thing?
Not interested in taking the salon ceiling down to correct this deal, just thinking some one has had this problem too. What did you do?
 
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Perhaps if you show a picture of the duct I could provide better info.

But, typically, they use insulated flex-duct in boats. It's quieter and has less condensation issues.

Though, when it starts to breakdown, it's likely time to replace as adhesive won't work well and it can off-gas.

Depending on how small the "chunks" are, you might be able to put filter media inside the duct behind the register to trap it before it comes out of the duct.
 
Boat Guy said:
Perhaps if you show a picture of the duct I could provide better info.

But, typically, they use insulated flex-duct in boats. It's quieter and has less condensation issues.

Though, when it starts to breakdown, it's likely time to replace as adhesive won't work well and it can off-gas.

Depending on how small the "chunks" are, you might be able to put filter media inside the duct behind the register to trap it before it comes out of the duct.
Click to expand...

All good ideas. I'll have to think about what material I can use to capsolate the remaining foam in. That off-gas issue is something to ponder. All depends if I can be it in there and extricate what ever debrie is coming through the plum. My parts book has no break down of the ceiling and how the auposteried defusers are attached. Got to find a way into the air duct at the delivery point/ceiling register, to do much of anything. Even installing some sort of bearer would require the removal and reinstilaton of the blasted vent.
Like most things of this nature it boils down to cabinetry 101 know how. Kind of hoping some one else has been down this road. I have found that learning how to do something like this through experperianc is expensive.
Attached is the only picture of the air duct system from my parts book. I'll forward pictures of the ceiling vent in a day or two when I get back on the boat.
 

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stephens013 said:
All good ideas. I'll have to think about what material I can use to capsolate the remaining foam in. That off-gas issue is something to ponder. All depends if I can be it in there and extricate what ever debrie is coming through the plum. My parts book has no break down of the ceiling and how the auposteried defusers are attached. Got to find a way into the air duct at the delivery point/ceiling register, to do much of anything. Even installing some sort of bearer would require the removal and reinstilaton of the blasted vent.
Like most things of this nature it boils down to cabinetry 101 know how. Kind of hoping some one else has been down this road. I have found that learning how to do something like this through experperianc is expensive.
Attached is the only picture of the air duct system from my parts book. I'll forward pictures of the ceiling vent in a day or two when I get back on the boat.
Click to expand...
I have the exact same issue... 2003 480 Sedan Bridge. Happens with the salon AC duct work. Leave boat for week and show up on weekend to black foam particles all over the couch and table. Like the idea of a filter, but need to figure out how to take off cabinet structure around the duct work.
 
In my experience, there is no foam in the conduit unless it's rigid. There is foam in the plenums at each end, and air dividers. I had one A/C that the fan's squirrel cage was slowly disintegrating, blowing little chunks of blade out until it broke. Warranty item, apparently a known issue. I am having a small issue with small pieces showing up on the salon couch, and I think it's probably the box behind the outlet, above the TV. However, it could be the outlet of the blower on the A/C unit. Those are relatively new, so I am leaning more towards the other end.
 
dstick said:
I have the exact same issue... 2003 480 Sedan Bridge. Happens with the salon AC duct work. Leave boat for week and show up on weekend to black foam particles all over the couch and table. Like the idea of a filter, but need to figure out how to take off cabinet structure around the duct work.
Click to expand...

I have the same boat and noticed the issue last spring. I can honestly say that it stopped on it's own after a few weeks.
 
dstick said:
I have the exact same issue... 2003 480 Sedan Bridge. Happens with the salon AC duct work. Leave boat for week and show up on weekend to black foam particles all over the couch and table. Like the idea of a filter, but need to figure out how to take off cabinet structure around the duct work.
Click to expand...

Well at least I'm not the only one splashing around in the sea of dead foam partials. Hate that others are seeing it as well but maybe great minds working her can conger up a fix.
My fan is ok, just air flow picking up the degraded insulation material. The pelum inside insulation is most likely the culperate but I'm not sure where that bad boy is either. The condincer is situated under the salon couch, easy enough to access. It's after that, where the 4 inch flex hose mianders that I'm having issue finding. One thing for sure, I'll vacume up this mess for a long long time before I start taking down the aupostered overhead; that ain't gonna happen. Just as a side bar I'm also seeing some of this mess in the master state room. Now that system is easier to access. I'll keep picking on it and see what I come up with.
Let you guys know
 
You should have the blower, maybe a splitter box on top of the blower outlet, conduit, and then at the other end, another aluminum/plastic box that turns the round conduit into a nice rectangular/square vent. I'd bet that's where the coating is letting go. If you can get behind the panel that has your outlet, you have found your plenum. If you have a splitter box, then it could be coming from that coating. Mine, fortunately are behind the cabinet wall over the TV in the salon, so access will be simple. Same for the other outlet in the Vee berth. The aft salon is a different system, and that one is a little tricker, especially if I want to remove it to re-coat. I'll post pics when I tackle it late next week.
 
370Dancer said:
You should have the blower, maybe a splitter box on top of the blower outlet, conduit, and then at the other end, another aluminum/plastic box that turns the round conduit into a nice rectangular/square vent. I'd bet that's where the coating is letting go. If you can get behind the panel that has your outlet, you have found your plenum. If you have a splitter box, then it could be coming from that coating. Mine, fortunately are behind the cabinet wall over the TV in the salon, so access will be simple. Same for the other outlet in the Vee berth. The aft salon is a different system, and that one is a little tricker, especially if I want to remove it to re-coat. I'll post pics when I tackle it late next week.
Click to expand...

Thanks for the heads up. I'll look in the over head cabinet above the couch. It's an anouiance that one would think there would be an easy fix.
 
I wonder if you could run slightly smaller hose inside existing one and use some kind of adapter to attach it to blower etc? That could save time to take cabin apart.
 
I have the exact same problem. 2003 480 Sedan Bridge. Have you guys come up with a solution?
 
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