Wallas Heater Total Confusion

OK, just this second came in from the boat to inspect the Webasto install after reading the Webasto installation manual, which says "Under no circumstances draw combustion air from an area occupied by people" or something to that effect. I also looked at the illustrations, and all I can say is, it is a good thing I did not attempt this install myself! In fact, the vent in the hanging locker door is simply to allow cabin air to reach the heated air return. The combustion air intake hose actually goes (although it was practically impossible to see without major contortions) through a neatly drilled hole into the area of the gunwale just forward of the gas filler tube, so it is drawing outside air for combustion in an area well protected from water. So unless we decide we need a second hot air outlet, I think we are in good shape!
 
The combustion air intake hose actually goes (although it was practically impossible to see without major contortions) through a neatly drilled hole into the area of the gunwale just forward of the gas filler tube
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Oh, Oh...that is not exactly a best-practice, I wouldn't think.

Do you really want to draw combustion air for a heater burner from near a gasoline filler opening?

I'm getting to the point where I think there need to be specific standards regarding the installation of cabin heaters...or do they already exist, and are simply being ignored?

Despite the various opinions, including my own, aren't there specific standards or codes which apply?
 
It is not near the gas filler opening - it is down under the gunwale where the tube goes through. Not a problem. No raw gas or gas fumes anywhere near it.

Karl":3q5x9v1a said:
Oh, Oh...that is not exactly a best-practice, I wouldn't think.

Do you really want to draw combustion air for a heater burner from near a gasoline filler opening?
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Pat,

"The combustion air intake hose actually goes (although it was practically impossible to see without major contortions) through a neatly drilled hole into the area of the gunwale just forward of the gas filler tube, so it is drawing outside air for combustion...."
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That would still make me nervous. Any errant fumes could change the intake air makeup, accelerating the combustion in the furnace. How much acceleration is speculation ..... but there could be quite a range IMHO.

Harvey
SleepyC :moon
 
OK, there is a standard for liquid-fueled marine heaters: ABYC A-7 Standard.

I haven't found a free version of it...ABYC has it as a $50 download!
Can someone who already has it post it?

From Webasto:

WARNING:
Do not extract combustion air from accommodation areas/
cabins! Danger of suffocation!

I don't claim to be an expert, but codes and standards generally do have some basis in fact, so let's see what the A-7 standard is (which the Webasto instruction is based upon).
 
Also, from Espar:

Combustion air intake
– The air for the heater combustion chamber must
not be sucked in from the passenger compartment
of the vessel.

I couldn't find the Wallas installation instructions...the scanmarine site is difficult to navigate, so maybe I just missed it.
 
For home furnaces, it's not uncommon for inside air to be used for combustion (wood burning fireplaces have operated this way for 1000's of years). In general, most residential codes require an opening to the outside 1 sq. inch/1000BTU's of furnace. Often this is accomplished with just a leaky house. However, these days the most common thing is to provide a vest for outside air to enter the furnace room. For home furnaces, the concern isn't oxygen depletion but the potential for the slight vacuum created to result in back drafting of exhaust with subsequent carbon monoxide poisoning.

For the Webasto and Wallas (both around 7000 BTU at the high output, the residential code for heaters would require a total of 7 sq. inches (or an opening of about 2.6" x 2.6" or a circular opening of a little less than 3" in diameter or about 0.03" of an inch crack around the edges of the door (assuming 17 linear feet around the door edges). On my 22, the combination of a hole under the gunnel through the bulkhead, the hole through which the shore power is fed, the hole for the anchor locker and the gaps around the edges of the door far exceed 7 sq. inches.
 
Well, it appears that the ABYC standards only apply to liquid-fueled cabin heaters installed by the manufacturer of the boat...a DIY (or, dealer) install is apparently not mandated to comply with the ABYC standard, so, do as you want.

I believe both C-Dory and Hewescraft are installing the Wallas cabin heaters with the "correct" combustion intake, utilizing outside air, however.

And, admittedly, I have yet to actually read the ABYC "A-7" standard pertaining to cabin heaters...hope somebody will post it, to shut me up if I'm wrong, and eliminate guessing and opinionating of other posters.
 
Karl":q37oqy0i said:
Well, it appears that the ABYC standards only apply to liquid-fueled cabin heaters installed by the manufacturer of the boat...a DIY (or, dealer) install is apparently not mandated to comply with the ABYC standard, so, do as you want.

I believe both C-Dory and Hewescraft are installing the Wallas cabin heaters with the "correct" combustion intake, utilizing outside air, however.

And, admittedly, I have yet to actually read the ABYC "A-7" standard pertaining to cabin heaters...hope somebody will post it, to shut me up if I'm wrong, and eliminate guessing and opinionating of other posters.
Click to expand...

I'd like to know too. It can't hurt a dang thing to hook it up if it is there.
 
I'm also surprised to see that the Wallas' furnaces seem to have only an exhaust line, and apparently use the cabin space for combustion air-supply.
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Not true. If you look closer you will see that the combustion air and the exhaust are all housed in a double walled flex hose. The unit does not use inside cabin air for combustion. It heats inside air and blows it back into the cabin. The intake is through the grill on the housing. If mounted under the sink for instance it would draw its air from around the galley cabinet doors, through the (in my case) existing grill that was for the Wallas as well as outside air through the gunnel raceway where all the other wiring runs from the cockpit to the cabin. So it would be a combination of inside and outside.
 
all this and for what. I guess ve miss the point. has someboby expired in the boat with a wallas running?
a better question might be 'how many wallassas have kepy how many people warm for how many years with out an incident?
some people just seem naturally bitter toward this brand and maybe if ve had many problems ve'd be amoung them. not so though, ve have zero problems for many years and stay warm too, in Alaska :lol: coarse, everyone knows alaskans are more pragmatic then cautious.
martin
 
There are check offs for "Electrical-Fuel Systems" and "Galley-Heating Systems".

Under these I usually only look at batteries and busses to confirm that at least the positive connections are covered and can not be accidentally shorted out by something like a dropped tool. The other big thing to check is the propane system if that is in use. Getting into exhaust connections, fuel line condition, gaskets, etc is beyond what we do.

The Safety Decal only attests to the fact that the boat is in compliance with Federal and State requirements.
That is not to say if we see something obviously or potentially dangerous or could have serious implications to health and safety that we won't point it out.
 
Minnow":1pw733rz said:
You must remember that you cannot make moisture or destroy moisture, you can only move it from one place to another.
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Not true, when you burn propane for instants the chemical reaction makes water:

Propane ( C3H8 ) will burn completely in excess oxygen to form water and carbon dioxide;
C3H8 + 5 O2 ---> 3 CO2 + 4 H2O

Additionally,

In the combustion of all fossil fuels (like diesel and kerosene) water is a waste product, and the overall reaction can be represented with the following chemical equation:

CnHm + (n + m/4) O2 → n CO2 + m/2 H2O.

Jay
 
Jay,

Nice to see a chemist on board. I think Minnow was mostly referring to the recirculating air that is warmed by the heater and the replacement air that comes in if inside air is used for combustion. His point being that bringing in outside air (which is colder) and warming it lowers the relative humidity in the cabin. Nonetheless the chemical reactions above definitely explain why stoves with the exhaust gas going outside are far superior to open flame stoves (like alcohol stoves) when it comes to keeping the cabin dry.
 
OMG...

Do we actually have a consensus on something, or will there be further rebuttal?

This forum is great for diversity of opinion, and diversity of facts, too...
I recommend that we each list our curriculum vitae as a sig file...

Or, maybe just talk about boating?
 
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