More Wallsa stove/heater trouble

[Alli Cat]

Another problem with the Wallas stove/heater....... This is a new dealer installed unit that works fine while at anchor or trolling. However, as soon as we start to run, the exhaust or some sort of incomplete combustion comes into the cabin from under the sink/stove location.

The thru hull location of the exhaust is located in the middle of the color stripe, which is below the rub rail. I think this might be too low.

I am wondering if any other Tomcat owners have had this problem and what is the location of your thru hull exhaust?

[Sea Wolf]

Fred-

This has been discussed before.

First of all, be sure that the seals on the exhaust port are tight. This includes clamps and sealants. High Temperature RTV sealant can be used to seal around fittings and hoses. Clamps must, of course, be tight. I'm not sure if there's room for doubled clamps like are used on fuel fittings, but that would be a good idea if possible.

Air pressure when running, particularly with a strong wind abeam on the side of the exhaust, can back up exhaust fumes into the area under the galley and into the cabin.

Another related problem is if the port is low and covered with water when under way in choppy seas.

The exhaust fan runs faster when the stove is on high, so some folks help solve the problem by turning the stove on high and opening a window if that's too much heat.

Some folks have reported having exhaust problems when docked at night with the wind on the beam to the exhaust side.

Others have reported the exhaust being sucked in the rear cabin doors and windows with the "station wagon effect" working.

I believe I suggested the wind pressure problem might be solved with the addition of a clam shell cover over the exhaust port, facing aft, of course.

We'll have to have someone with a Tomcat like yours measure their exhaust port height to see if that's a contributing problem.

More to come from other folks, I'm sure.

Good Luck!

Joe.

[drjohn71a]

Ally Cat,

Sea Wolf pretty much covered the gamut of previous related strings.

I checked my photo album on this site and it looks like my Wallas vent is about 3 inches ABOVE the gunwale. The TomCat design seems to throw around quite a bit of water at speed, especially in any kind of seas, so a vent BELOW the hull stripe seems pretty hazardous at first glance. Are you sure it is this low?

In spite of this, we initially had a great deal of problems initially with fumes being drawn into the cabin while running at moderate speed or at anchor/moorage with wind into the exhaust opening.

Turns out there was some loose part on my Wallas' fan - maybe that had some effect???

Anyway, I have noticed no problems this last 1 1/2 years of running.

The major contributor we found was running with most windows closed and the back cabin door open. That sucked in fumes from the aft and thru the vent. Cracking the front center window helped us with fogging and also seemed to create more positive pressure in the cabin. Cracking the front center and the two front side windows, all three together, pretty much ended the problem if the aft cabin door was closed.

With all windows closed and the cabin door open, fumes were being sucked into the cabin from engines, and anything on the aft area and also back pressure on the Wallas exhaust. Opening only the two aft side windows created some suction, but not as severe as having only the cabin door open.

Soooo it seems best to start opening windows at the front center, then the front side and see if that helps reduce the backwash of Wallas exhaust fumes. The further aft you open, the more suction effect it seems.

At anchor or tied to a float, if the Starboard wind seems to force fumes backwards into the cabin, try tying a sideline to the anchor line and draw it aft and tie it to change the angle of the boat to the wind. At a windward dock, let the aft line off and maybe use two offset forward springs to get a 25-30 degree angle to the prevailing wind on a lee dock. It does not seem to require too large an angle to stop the back flow. They make a big SS clam vent that is sold/ordered at West Marine and we considered putting such a baffle over the Wallas exhaust, but now just control the problem with a slight change in attitude (boat attitude!).

Good Luck,

John

[Sea Wolf]

Here's the clamshell vents available at West Marine:





Click on the photo for the link to the clamshells. They're made in sizes of 1", 2", and a 4" openings, in stainless steel, which you'd have to use because of the heat.

Did anyone try my suggestion of using the vent shield over the exhaust opening?

((I have propane heat from a Force 10 Cozy Cabin heater and a 3 burner propane cook top by Wedgewood, so can't test it out myself.)

Joe.

[MOOSE]

[Alli Cat]

Thanks for all of the info from all of you. I will try to find a clamshell that will fit. Those dorks at the dealer placed the thru hull so close to the sink drain thru hull that I am having trouble finding one to fit. But I will find one, and then we can move on to fun stuff like organizing and customizing cabinets etc.

Fred

[Jack in Alaska]

Fred,
I assume your dealer is AMD..??? Good luck with that.
Jack............

[drjohn71a]

Alli,

If your Wallas exhaust is truly below the gunwale line, it could be a very dangerous situation if you get into any kind of rough seas. While the sink drain outlet is a watertight hose fitting, the Wallas opening consists of the the exhaust tube with an open space around it and some glass type insulation. As such, water could easily enter your hull thru the Wallas exhaust opening.

You definitely need to move the Wallas exhaust to the cabin side ABOVE the gunwale and patch the hole you have with a plate of some sort, or fiberglass repair, etc.. You could ask Dr. Bob of Thataway about what he thinks.

I think your dealer needs to arrange for this change at no cost to you. Your boat could SINK from this installation error.


John

[drjohn71a]

Just to square things off since I've had a question about this:

I do not know anything about the proper location of a Wallas' exhaust on a CD22 model. The 22's seem to ride higher in the water and have more of that "dory flare" than do the TomCat models. That side flare throws the water away from the hull better on a CD 22 than on a TC255.

I have an aft control station, so I can observe the water against the TomCat hull easily. The TomCat hull rides deeper in the water than does a CD22 and is more vertical with almost no flare to throw the water off to the side as happens in the CD22.

So, maybe a Wallas' exhaust on a CD22 is OK down under the color stripe. I personally do not know about that.

I have observed very heavy side wave and general running water action to be very heavy up to the aft half gunwale on my loaded TomCat. That is why I am thinking that is not a good place for a Wallas' exhaust.

More knowledgeable ppl than I may know better than that, and that's fine with me, if they really know what happens down there in high seas, high winds, storms, and differing running positions.

John

[breausaw]

Here’s a quote directly from Scan marine, it addresses the issue of air pressure pushing exhaust back through the exhaust port; go to the link and scroll down. Next year I’m going to install an intake/exhaust cowl or clamshell vent as Joe refers to it. but will duct tape in place first to make sure the location actually works.

Also if you scroll down more they address Exhaust routing, a lot of good information here.

http://www.scanmarineusa.com/techtalk_WallasProductTips.pdf

a. Fast boats:
When mounted on fast boats, there can be problems encountered
with air pressure being pushed into the exhaust port of any forced air
heating or cooking product, compromising the burn process. To stop
this from happening, it is recommended that a wind break of some
kind be mounted just ahead of the exhaust port on the side of the hull.
A good test is to mount vertically a 4” long piece of 2” x 2” wood to
the side of the boat just ahead of the through hull. This can be done
with double back tape for the purposes of a test.
The wind break will produce a negative pressure zone immediately
behind it when the boat is at speed. For permanent installations, an
engine room air intake/exhaust cowl can be mounted facing aft to
act as the wind break. The cowl should be mounted with the trailing
edge of the cowl in line with the leading edge of the exhaust outlet
hole (see Figure 1). This location will prevent the cowl from getting
very hot in still air conditions.

[Byrdman]

I have also found it helpful to put a simple bright yellow dot on the bottom edge of the boat wall (inside) or window above the exhaust hole.. This only helps remind me where the exhaust hole is when docking...or when getting help tie up the boat....and to watch for fender lines in line with the yellow dot....which means I will have a melting fender....if they line up. Move the fender...and, if docking where there is a rubber rub railing.... put a fender close to the the exhaust, as to not burn the dock....or fender. It smells bad...

[Alli Cat]

I have spoke to Doug at Scan Marine and he has been helpful regarding the clamshell and the test using the wood/tape, so we will give these a try.

I have also put in an e-mail to Frank at C-Dory to get their take on the location of the exhaust thru hull.

Fred

[Captains Cat]

I've been without the Wallas all summer because it wouldn't start/do anything at all. Checked fuses and they seemed OK, just didn't seem to have power.

This morning, I had a marine mechanic/electrician down to look at it, along with a bilge pump and ws wiper. We decided not to do the work today because it's blowing 40+ and water is coming up to the top of the pier. We got on the boat though to show him where things were and I turned the batt switches on to power things up.

When I got to the Wallas problem, I told him that when I turned the little power switch on, the yellow light should light up (which it had not been doing). This time it DID!! Then I turned up the temp on the knob, saying that when I did this, the red light should come on. It DID. And lo and behold, the stove fired up and began to blow warm air! Oh well.... He must be a genius, just had to look at it and it works. The engines weren't even running, nor was I on shore power.

He's coming back next week to be sure the spell is still working and to fix the bilge pump and ws wiper!

Raining hard here now, NorEaster coming in for a couple of days. Time to hunker down with a cuppa...

Charlie

[garyk]

Fred,
As stated in other post, the exhaust certainly should be above the rub rail. We have a 2006 Tomcat and had the same problems as you . Worked fine when not underpower. Fought this for a full season. Added the 4'' clamshell and haven't had a problem since.
The Tomcat is a fantastic boat, we took ours to SE Alaska the summer of 2006 and '07. 6000 mi. those two summers. You should have much pleasure out of Seward, Homer and P.W. Sound.
I'm from Anchorage and have two sons still living there and one who is a guide, Butch King , Wildman Lodge on the Alaskan Peninsula.

Gary King

[Doryman]