Converting to a Wallas

[Dora~Jean]

Absolutely, cross-sectional area. Also the type/smoothness of the ducting. She said it's flexible, therefore probably ribbed which will increase that backpressure too. Still, 2 1/2 ft will work just fine on my boat, it will exit at the upper left corner of the cabinet next to the sink towards the isle. I was thinking cute and route from that cabinet to under the helm seat cabinet and exit upper right corner of it -- thus lowering the exit point maybe a foot to get the warm air down lower. Down side, more ducting, an additional 2-3" hole in the back of that cabinet to route, plus a bit more difficulty routing the exhaust tube due to the mounting orientation. Just not worth it for my installation. KISS principle still rules.

Thanks for all the tips, can't wait to get it, about 2 wks...I'll post pictures for sure.

Steve

[Sea Wolf]

Dan, Steve, et al:

Good point about x-sectional area, something that I didn't think of!

Now at the risk of being "gonged" by the resident "KISS" Police, I'm going to discuss this further (!)

First of all, just like the Alaska pipeline, ducting warm air has it's obvious difficulties. Besides the drag or resistance to flow, there's got to be a great tendency to lose the heat along the route. When using the PVC / spiral wraped wire flex tube, a point of diminiishing returns is gradually approached as the duct is lengthened. Other ducting materials and insulation can obviously lessen the rate of this loss, but the same phenomena eventually results, albeit over a greater distance.

With the C-Dory, the need to duct heat into the V-berth and also down to the floor quickly run up against this length related problem as well as problems of where and how to position the ducting.

For the v-berth, crossing the gap from the galley cabinet and proceeding through the dash bulkhead is the first problem to deal with, particularly in the light of aesthetic considerations. Designing an under-gunnel route down by the wiring channel would be the easiest choice to yield a hidden installation, although the route is starting to lengthen out a bit, depending on where the heater is to be mounted.

Then too, one would really want to take the heated air up to the peak of the bow area to get a better mix with the cold air, rather than just dump it behind the dash where it can easily return to the main cabin and leave the cold air in the v-berth basically unwarmed.

For the floor heating, another related problem quickly occurs: after routing the warm air down to the floor, it will quickly return directly to the top of the cabin because of its lighter, warm air bouyancy, rather than throughly mixing with the cold air below. Therefore, we'll apparently have to add a mixing fan here.

These problems of ducting are not insurmountable, of course, and can be solved by insulating the ducting, enlarging its diameter, and/or using booster fans as we've mentioned.

I faced these same issues when I installed the propane heater in my boat, and here's how I think I solved them, which is kind of a "backdoor" approach: (Tell me if you think I'm deluding myself!)


When considering the problems of ducting or pushing warm air down and getting it mixed with cold air on the floor, it occured to me that it might be a lot easier simply to lift the cold air off the floor, mix it with the warm air near the heater, and then let the body of warm mixed air (and its termocline) gradually lower itself to the floor level, eliminating the stratification that way.

It just seemed easier to lift cold air up and blow it into the area around the heater than to specifically duct it downward and then be faced with a mixing problem. The energy required to lift the cold air and the energy required to force the warm air down are probably equal, but this method eliminates the forced mixing at floor level. Plus the final stage of the lifting process can be used to blow the cold air over the heater, resulting in a more efficient energy transfer, another bonus!

One more benefit results from this approach. We don't have to duct heat to other compartments like the v-berth. Cold dense air from the berth area will flow downward and out to the floor pick up point. Warm air from the deepening mixed warm air mass moves into the berth area in the process, thus eliminating any need for ducting there.

Because of this approach, we can just build a cold air lifting duct system for the most part hidden inside the galley cabinet.

It should be pointed out that I figured out that two computer fans, placed more or less in series, would circulate the entire cabin air volume in under 10 minutes. (Difficult to calculate the cabin volume exactly.)

Does this sound reasonable, or is there something I'm missing?

Crazy Joe w/o funny business tonight!

[Dora~Jean]

Joe,

Wow, a bit detailed for my pea brain at 11:30pm just before bedtime, but I like the approach -- let natural convection do most of the mixing. I plan to mount the heater in the upper shelf against the left wall behind, under and to the left of the sink. With the cabinet doors closed, I'd like more 'return' air to get back to the heater inlet (on bottom of heater) than the leakage of the closed door gaps. So I plan on putting another register just like the heat output register but thru the kickpanel at the bottom of the cabinet -- no duct, just a hole. This will in effect have the same result as you explained, it will suck in the coldest air on the floor, run it through the heater and pump out warmed air about 3 ft higher (output register vanes will be pointed down to help this flow). Should work, just don't know how well or if it will reach the V-berth area to suck that cold air out very much.

Steve

[Dora~Jean]

The Wallas 1300 heater install has begun! Got the 3/4" thick wood mounting plate glued to the hull (a la 3M 5200) inside the upper cabinet under the sink, so the position has been 'chosen'. Exhaust tube ordered to length, 3 ft.

I read most all of the comments and problems including 'burning' side trailer bunks - ouch! For exterior aesthetics I'd like to co-locate this thru-hull (about 3" dia) near the sink water outlet as I've seen on many boats. What I haven't seen is this thru-hull 'above' the water outlet, which would be the most convenient for inside routing, will easily clear the side bunks for exhaust heat and still leave a good 9" gooseneck above the thru-hull to prevent water intrusion.

My question: Is there something 'sacrilegious' about putting a fitting/hole in the boot stripe area?

Steve

[dogon dory]

Sorry, Folks - Post Deleted By Author

[Dora~Jean]

Beg my pardon Dan, I thought there was SOMETHING wrong about 'boot stripe' -- you're right, sheer stripe is what I meant, just below the gunwale. Thanks!

So, is this a taboo (not "tyboo"...) area to mount a 3" SS flange? Don't want to disturb the CD gods ya know. Like a Harley, there are certain things you just don't do...

Steve

[Dora~Jean]

I'm proud to announce the Wallas 1300 Heater installation is now complete -- with a few cuts and some very sore muscles thrown in (working upside down inside the back of a cabinet). I documented several of the key areas in My Photos (or in the Detail Photos section). This unit is a quality product just like their 1 and 2 burner stoves, very tightly packed in a compact package -- so small, it looks like something built for a spacecraft!

For those interested, here's a quick run-down on what I did. On a scale of 1-10 (10 being most difficult), I'd say this installation was about an 8.5 -- not particularly due to the heater, but rather where I chose to locate it. I didn't want it to take away any usable space if possible and not be an eyesore either. Under the galley cabinet seemed plausible since this unit remains cool to the touch, except for the intake/exhaust tubing at sharp bends, and there are no flames or accessibility of the combustion chamber from the cabin.

The most difficult part was locating the unit in 'exactly' the right spot to 1) Allow 8-9" of 'gooseneck' from the side thru hull intake/exhaust fitting to the highest point of the connected tube into to heater unit; and 2) Allow the maximum of 3 ft of ducting to reach a suitable spot to mount the output heat register. I wanted the heat flow to be directed to the center of the cabin and the intake cold air from the floor, both achieved.

Bending the dual SS intake/exhaust tube was hefty, difficult and a 'must wear heavy gloves' situation -- that explains my cuts before the gloves went on... Took me about 2 hrs to bend it for best fit BEFORE installing it together with everything else. Where I put it required that the bracket holding the unit to the plywood glued to the wall be screwed in place at the same time as the intake/exhaust tube and attaching the heater to the bracket all be done simultaneously! That was tough. Also fabricated a heat shield at the first bend out of the heater to avoid overheating the fiberglass above or the trunk wiring nearby, used 1/4" standoffs on top of the shield to space it off the fiberglass.

I decided to parallel another 30 ft of 2-cond 8 AWG wire from the battery switch to the windlass while adding a tap under the galley to supply the Wallas with hefty juice. When I calculated the original windlass wiring gauge, I didn't do a good job accounting for the extra wire needed for all the routing to/from various points, in short, the wire gauge chosen should have been 6 AWG, so paralleling another 8 AWG provided the extra copper needed. BTW, that 30 ft of wire is about $130 -- ouch...

I had to cut a 3" hole in the shelf between the upper and lower cabinet areas to get the return air through to the heater from the bottom of the cabinet mounted intake register. This hole also served as a good route for the intake and return tubes to the fuel resevoir. Important note from the Wallas installation instructions -- make sure there are no droops/loops on the return fuel line (black) from the heater to the resevoir, will cause blockage and erratic operation of the heater.

Lastly I added a Wallas remote switch with a LED in the switch that mimics the light on the heater unit to indicate combustion in progress. The remote switch comes with about 25 ft of 4 conductor wire for 'very remote' locations. I cut it down to about 4 ft to match my location. It had to be cut anyway though to feed it through the rubber grommet in the bottom of the heater to the circuit board just inside the rear panel (requires unscrewing the rear panel and tilting out just enough to plug in the 4 conductor connector). No instructions came with this switch, but was fairly intuitively obvious. I called Scan Marine and asked if the main switch should be ON or OFF for the remote switch to work, they didn't know. Afterwards I told them OFF works just fine!

After all was completed, I checked over everything one more time, took a deep breath, sat back and flipped the remote switch ON. Woah, it came to life...! I intently watched as the fuel inched its way up the translucent intake tube to the main unit, about 1 inch a second for the 4 ft it had to go. Then a few other sounds and bingo, heat began coming out. I ran outside and down to the ground and felt the exhaust heat coming out beautifully with only a very slight hint of a kerosine odor (Klean Heat by Klean Strip has a very low odor to start with). I measured 5.0 amps during startup, about 3-4 minutes (the manual said 4.0 amps I believe), and 0.4 amps during operation. Incredibly low current and very quiet operation. The airflow is great, quite substantial, it easily fills the cabin with warm air -- a little unfair assessment though, it was only about 50-55 deg at the time.

I let it run for over an hour (this is midnight to 1am BTW on a night I have to get up for work at 6:30am), I wanted to get past the infamous "30 minute syndrome" I've read about from some folks on their stoves. For me, it was just short of a religious experience to watch that Wallas work so efficiently, clean and quiet. All I can say is wow, well worth the effort and cost.

Costs: $850 heater unit, $20 fuel tank (1.5 gal), $95 combo intake/exhaust lead thru hull fitting (SS and sealed), $75 Remote Control Switch, $30 for 3" heat output register, $60 for 3 ft of SS intake/exhaust tubing and $12 for output heat duct and some shipping/handling. Total: $1,150 (bandaids not incl).

[Sea Wolf]

Steve-

Excellent installation!!!

Very clean, neat, and well thought out! Shows fine craftsmanship and attention to detail, too.

You get seven Purple Hearts and the Annual Houdinni Award too! (Gold Plated Handcuff Keys attached to a Pocket Periscope and Snorkel Tube)

The account and photo essay are great, and we need to get the photos and captions also into the Photo Details section of the Cabin and Interior Forum in the Library. This text will automatically go under the discussions part, of course, but it would be nice to have the pictures there too where folks browsing the photos will come across them, rather than have to come across them through the link in the discussion.

Congratulations on a job very well done!!!

Joe.

[Dora~Jean]

Thanks for the kind words Joe. I agree, the installation came out pretty good in spite of myself!

Good suggestion to 'move' the photos to the detail photo section. I just did -- sort of. Thought I'd get cute and do the "URL section move option". Hmmm, got myself into trouble, moved photos and a whole bunch of icons and other 'stuff' - YIKES! Can't delete as a user...BUT...found that I could 'move' them, so I did, moved them to my own folder where I could then DELETE them...

[Dora~Jean]

Well heck, it was 'down' to 55 deg this morning (hey...SoCal remember...), so just had to go out and fire up the Wallas in the backyard for awhile!

Took some measurements for you electronical types, all voltages measured at Wallas connection point:

Starting Voltage (no load): 12.25v
At 2 min 40 sec (5.5 amps): 11.90v (glow element now just OFF)
At 3 min 30 sec (0.4 amps): 12.05v (warm air felt)
At 5 min 0 sec (0.4 amps): 12.10v (Switch LED light ON)
At 17 min 0 sec (0.4 amps): 12.15v (Switched unit OFF)
At 23 min 30 sec (0.0 amps): 12.20v (Fan OFF, LED OFF)

Also measured voltage at the battery 14 ft away during the 5.5 amp startup sequence, delta was 0.15 volts -- not too shabby.

[catdogcat]

Very, very nice install. I am thinking about duplicating this entire setup. Couple of questions since there seems to be some experts here. How do you think this heater will do in Alaska? Will it keep the cabin warm in below 30 f temps? Second, Dora Jean...are you worried about sea water getting in through the exhaust?

[Dora~Jean]

catdogcat,

Thanks. I can't answer for this heater's effectiveness in 30 deg weather, but with the windows closed, I'd think it will do just fine in any C-Dory. It puts out 4,000 btu, constant. The Wallas 125 dual burner stove that most people have put out 2,000-6,000 btu. That puts the 1300 right in the middle.

As far as water intrusion, funny you should ask. Yesterday on the very quick "Channel Islands Quickie Cruise", we encountered some fairly nasty waves, many of which hit me on the starboard side that I'm sure submerged or doused the combo intake/exhaust thru-hull well. I checked the inside for any water intrusion very carefully after getting back onto the trailer, none whatsoever! I used high temperature silicon around the exhaust and intake tube fittings before sliding on the tubes and clamping in place. The thru-hull and tubes themselves are stainless steel and sealed.

One very nice unit.

[Sea Wolf]

catdogcat-

To put the 4,000 BTU output in perspective-

A standard propane or gas stove top burner puts out 6000 BTUs-

which is equivalent to a standard small room electric heater of about 1800 watts running on the "High" setting.*

My Force 10 Cozy Cabin propane heater keeps up with my 22 set on about

2,000 BTUs in 35-50 degree weather

4,000 BTUs in 25-35 degree weather

and the 6,000 BTU setting should be good down to about 15 degrees, as a guess (this is California speaking)

Red Fox uses the same heater anchored overnight next to the glaciers in PWS and elsewhere in Alaska.

The only other thing to think about is that the Wallas 1300 has a fixed output of 4,000 BTUs and cannoat be dialed up or down, or turned on and off in short cycles by a thermostat. You turn it on and ventilate extra heat to suit. Also keep in mind Steve's Dora Jean is also a CD-25, not a 22.

On the now archived C-Dog site, Dale installed a Toyatomi forced air furnace like the W-1300, and found it was a bit too much for a CD-22 Angler (smaller cabin yet!) in the California Delta. OTOH, better to be able to open the window and cool down with too much heat, rather than have too little!

***********************************************************

* The BTU output is for a 1 minute period, so

6,000 BTUs in 60 seconds is 100 BTUs per second, and

1 BTU = 17.57 watts, so

100 BTUs = 1757 watts!

(some unit conversion omitted)

***********************************************************

Joe.



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[Dora~Jean]

Yep, my same thinking Joe, better to have too much heat than not enough if it's going to be a fixed output. It uses very little fuel, about 3 ozs per hr according to Scan Marine, so it's not going to break the boat-money bank like gasolene is doing...

One advantage of slightly more BTU's than needed is it will heat the cabin up a little faster after coming in from a cold dive or damp evening on shore! An advantage of its fixed output is that I don't have to remember to turn up the heat for a few minutes before shutting it down -- to burn away any soot accumulation or whatever.

[MOOSE]