Install Wallas heater in a Hunter 41 ac

Mar 20, 2021
14
Hunter 41 Lake Tahoe
Hello , looking for someone that has installed a Wallas diesel hot air heater in a Hunter 41.
Would like to get info on unit location, where you ran ducts and where to vent the exhaust.
Thanks
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,135
CAL 35 Cruiser #21 moored EVERETT WA
I installed my Wallas, and while not on a Hunter 41, there are some universal considerations.
  1. Locate unit where you can supply it with diesel
  2. Know that the heater will use a fan to move the heated air into the cabin so location of heater should be where fan noise will be minimized
  3. You need both heating ductwork and return air ductwork
  4. Insulation around the heated air ducts will maximize the warm air in the boat
  5. Exhaust should be in the stern quarter at least 4ft from the transom so that exhaust fumes do not get captured behind the transom
  6. Follow the rules for the water loop height in running the exhaust
Good luck. I love my Wallas heater.
 
Dec 25, 2000
5,932
Hunter Passage 42 Shelter Bay, WA
All good suggestions that John makes. What model do you have? Also a different model boat here, but wrote an article on our self installed Wallas 40D and the outcome. Hunter 42 Owner Modifications and Upgrades

If you want your boat to smell like your engine room, avoid installing it in your engine room as some have advised. Installed ours in 2006 so that we could enjoy cruising year around in comfort. No return air ducting required with ours as I installed it in a stern transom locker. The exhaust pipe and related insulation sock is pricey, so keep the furnace close to an outside bulkhead/hull.
 
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Jul 27, 2011
5,134
Bavaria 38E Alamitos Bay
No return air ducting required with ours as I installed it in a stern transom locker. The exhaust pipe and related insulation sock is pricey, so keep the furnace close to an outside bulkhead/hull.
My factory-installed Espar is far aft in the std locker right below its exhaust port HIGH on the stb quarter, and two or three ft aft of the diesel tank (stb) that supplies it. Good overall, but the heat distribution in the boat favors the aft sections—the aft (stb) head, aft (port) cabin and salon, fortunately. Ducting to port side aft cabin runs direct, not around rudder post. Forward of fwd bulkhead—the fwd cabin—not so good. Stays rather chilly up there. I usually shut its vent and close it off (door) when just admiral and me aboard. Occupy only the aforementioned sections when out in cold weather. If I monkeyed with the ducting I might improve heat flow up there, but have not done that. It’s good enough as it is!

No return ducting on this one. In addition to the sound of the blower, there’s the sound of the pump supplying the diesel fuel. Not really too disagreeable.

You want that exhaust port far aft so when swinging at anchor in wind & running the heater, the exhaust itself does not blow over the cockpit with any cross wind, etc. So, I’d recommend very far aft to just fwd of where the topsides meets the transom, and high, just below the gunwale. That should keep it (exhaust) from beneath the transom as well.
 
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jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,135
CAL 35 Cruiser #21 moored EVERETT WA
From the Wallas Manual, bold emphasis by me.

Exhaust pipe​
The longest permissible exhaust gas pipe is 13ft. Exhaust runs over 8’ should not have more than 360 degrees of turns. Turns should be as long radius as the installation allows.​
The exhaust through hull fitting may be installed into the hull, the transom or the deck, depending on fitting type, hull design and other factors. If a deck fitting is desired and heavy water on deck is expected, then a closeable deck fitting (2460) with an extension (2069) should be used. On heeling sailboat through hull applications, the through hull fitting should be installed as far aft as possible, preferably at the stern. Recommended distance from the through hull fitting to the surface of the water is at least 12 inches.​
Exhaust gas is hot! The exhaust pipe and fittings must be insulated well and installed away from flammable materials. Air must be allowed to flow freely past either the through hull or deck fitting. Please contact Scan Marine for information.​

Here is a link that provides one owners install.
 
Mar 20, 2021
14
Hunter 41 Lake Tahoe
Hi, thank you all for your ideas and suggestions.
I am going to go with a Wallas Spartan mounted in the port side aft locker.
 
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Jul 27, 2011
5,134
Bavaria 38E Alamitos Bay
Hi, thank you all for your ideas and suggestions.
I am going to go with a Wallas Spartan mounted in the port side aft locker.
Good luck with it. Having diesel-fired heat aboard has made our outings more enjoyable. We use it often:).