Diesel Forced air Exhaust from pilothouse roof?

[Geoff Ferrell]

All,

I've been web-window-shopping & reading for a while on this. My intention is to install a Planar, right below the pilothouse helming seat and almost right under existing AC unit. Plenty of room and great access to the AC Ducts at their source.

My question is about the exhaust. Better A. straight up & out the pilothouse roof OR B. out the side of the Pilothouse (would be right under the middle window if you are looking at the pic). The transom is too far and tortuous (and heat rises).

I'm leaning to B. definitely far enough above any heel or broach - just a caution for going forward when the heat is on.

I assume the inlet could be at the rear of the pilothouse (stationwagon effect?).

Geoff

SV Callae Jane 38PH Cabo Rico

[tkeithlu]

Hmmmm. You can't readily do concentric inlet and exhaust pipe like you can with many diesel/propane heaters. It's also ugly as hell so under the seat sounds like a good idea. You're burning diesel. Either way I'd wrap the exhaust with insulating tape to avoid burns. The out-the-side option has a couple of problems that come to mind: soot on the side of the wheelhouse and the port, and heat there, too. Unless your wheelhouse is a bunch tighter than most, "in" can be ambient air in the wheelhouse. I doubt that you are going to pull a suction.

I can't fully envision what the two installations will look like, but as a decision-making process, I'd want a good reason not to put the stack out the top before I went with the side mount. Would it get in the way of running rigging?

[Geoff Ferrell]

Thanks tkeithlu,

I hadn't worried about soot (always got clean burns from a Dickenson Diesel on a previous boat) but you're right.



i was thinking about the side exit because I could then 'hide' the exhaust pipe (see interior pilothouse pic). But there would be no issue with rigging or lines on top - the boom is +2ft above it and traveler would be 3ft behind it.



Where the exhaust is open in the cabin (Purple lines on the attached pic) I could wrap it with a shield - or wrap/insulate it. Do you think there would be a downside to just shielding it (stainless perforated pipe)?

[steffan]

Originally Posted by Geoff Ferrell

All,

I assume the inlet could be at the rear of the pilothouse (stationwagon effect?).

The Planar instructions will advise against putting the inlet and exhaust on different sides. I believe the theory is to lessen the chance of wind creating lower pressure at the inlet vs exhaust, leading to combustion air backflow.

I went with an external inlet a couple of feet over from the exhaust, just plastic tubing and fitting. Childsplay compared with the exhaust if you go that route.

[more]

Originally Posted by steffan

The Planar instructions will advise against putting the inlet and exhaust on different sides. I believe the theory is to lessen the chance of wind creating lower pressure at the inlet vs exhaust, leading to combustion air backflow.

in car

[CaptTom]

Personally, I'd go through the cabin side. Your exhaust fitting will have an air gap, even if it's not a co-axial intake/exhaust, so heat shouldn't be an issue. Soot is easy enough to wipe away. Less danger of rain or spray getting in. Shorter exhaust. No ugly pipe in the cabin.

I'd wrap it with the manifold wrap they sell for race cars. The Planar exhaust gets red-hot.

I suppose wind pressure could be a problem. My exhaust is low on the transom so at anchor, this isn't a big deal. I doubt having the intake on the exterior would make it any better though.

[wrwakefield]

We also have a pilothouse with an Espar forced air diesel heater. The exhaust temperature is hot enough to cause burns. [I just turned my Espar D5L (5KW) on high and measured 241°F at the exhaust port.]

I haven't seen an exhaust fitting for horizontal surfaces for these heaters.

I wouldn't place our exhaust outlet under our pilothouse windows because we need to walk past those points on the narrow deck, and skin/rain gear could definately be impacted if someone stopped next to it while the heater was running.

Ours is instead positioned through the hull just under the toe rail and above our rub rail as shown in the photos, below. [On the inside of the hull, the exhaust line loops up to help mitigate water ingress. There is also a water drain in the exhaust line before it attaches to the heater.]




Close-up of exhaust fitting with custom SS diverter welded on to deflect rain water.


In case this is useful.

Cheers! Bill

PS: Our heater- and it's combustion air inlet- is in our ventilated, isolated engine room. Heater make-up air is drawn from a midship cabin which has a port part way open most of the year. This assures there is some fresh air mixing with the recirculated air being distributed throughout the boat.

[steffan]

Originally Posted by more

in car

Also in boat, per the Planar instructions. References a boat specifically, with diagrams/illustrations.

[jamhass]

I agree with what Bill said. In addition, I might add 2 considerations.

One is noise. Does your plan include a muffler, and if not, can you handle the noise? Our Espar exhaust was noisy, and neighbors across the fairway took note.

Second, if exiting through the roof is the need for a rain-diverter. Often these heaters' have strict back-pressure restraints, and rain diverter exhausts may (I only mean may) violate those restraints.