Diesel Heater Project

[Delta Riverat]

Heater in with electrical verified, sealant, clamps, exhaust lagging, hold downs and fuel input.

Next the last part the fuel tank, lines, filter and pump. Soon -

 

[Delta Riverat]

This is the "electrical box"

I tapped into the fridge circuit for power which also powers the 12 volt fridge compartment exhaust fan. The run from the engine room is 12g and I was thinking that if I was attempting to start the heater when the fridge was in defrost mode the current could exceed 20A and the voltage drop would be excessive as well as the current so I added a "ballast battery", a 20 AH Renogy LiFePO4 battery to accommodate this possible event. The bridge wiring is all 14g with 15A fuses to the heater supply and the battery. The battery is retained from moving sideways by the little wood rail with L brackets and up by this cover;

 

[NoRain]

What kind of fridge do you have that has a defrost cycle on 12V?

 

[Delta Riverat]

Dometic DMC 4081

 

[NoRain]

Well huh, learn something new every day. Never heard of auto-defrost on 12V.

 

[Delta Riverat]

Yeah, the wonders of modern tech eh?

The compressor only uses say 5-7 amps, but I did see a big draw once on the shunt and the fridge wasn't even running (slight compressor noise when running) so it must have been the defroster. The fridge has a max spec of 13A and that's twice what the compressor uses.

 

[Delta Riverat]

Tank in and SS feed pipe off tank installed.

Got one of those "tap into fuel tank" kits and repurposed it to flow rather than draw. Wanted metal on the outside run. Came out pretty nice me thinks, well protected and easy access.

 

[Delta Riverat]

It's in and it works!

It fired right up after priming, no errors, no leaks and no smoke. A bit of diesel fumes and then the heat started to build. A lot of heat. Too much heat...

For the microwave cab. No, I didn't kill the microwave, but it was very warm. Not a problem, plan b was always in my mind when I started. It will be easy to duct the heater through the top of the cabinet and out the front. Was just trying to avoid drilling that 3 inch hole though the nice teak.

Yeah, these things really cook, glad I lagged that exhaust pipe, thanks all. I will need that muffler, it's loud outside without it. After all, I only have a 1 foot exhaust run. The though hull worked great, not even warm on the outer ring. So another trip to the depot for some 3 inch galvanized to run through the top of the microwave cabinet and all that hot air will be spewing out the vent w/o heating up the cabinet. It comes out with some serious velocity too, the stock down vent should work well.

 

[luna]

Its good to see that you have realized how much heat comes out of these things and are planning to duct it around the poor overworked microwave.

If it was me and I had the room, I would once through the bulkhead into the microwave cabinet, upsize to 4" duct and then split that 4" duct to 2, 4" ducts and using two register duct boots feed air through those 2 louvers over the microwave. Rigidly mount and insulate all of the duct work as you go.

Then, go buy a few cases of JD.

 

[Mac2]

Well done! You have to be very satisfied with the success of your ingenuity.

 

[Delta Riverat]

Thanks and yes I am -

Just need to fix that venting issue and fix a muffler on the outside.

Going to run a separate vent, the one that came with the kit. The existing nice wood louver still vents the AC.

 

[BruceK]

Don`t the "original" types have a combined "air in exhaust out" tube, with the exhaust tube inside the air tube so the hot exhaust is insulated and cooled by incoming air? Is that complex tubing available without the "original"heater unit?

 

[Bmarler]

Don`t the "original" types have a combined "air in exhaust out" tube, with the exhaust tube inside the air tube so the hot exhaust is insulated and cooled by incoming air? Is that complex tubing available without the "original"heater unit?

The only ones with balanced combustion air was wallas. (I think) espar didn’t have it. It would have been nice though, but I think bringing in cold combustion air is part of the equation for clean combustion. Sort of like bringing cold air to the intake of a car engine.

 

[Delta Riverat]

I got this baby wrapped up today. Pulled the microwave (one more time) and installed the duct. A 2 foot run and another 90 degree adjustable which I set as an offset.

After I got that in I ran it again for test and it worked great, that hot air (and I do mean hot, you don't want to get any closer than 2 feet) came shooting right out and well into the room, you can still feel it more than half way to the helm. On to the exhaust;

As said, I do need the muffler, it's loud w/o it. Used that stuff that came with the kit to bend it up to the deck of the fly where the wind can take it away and it won't get sucked back into the intake. Bonus is one screw and it's off for stash until next winter. My pump is also pretty quiet, can't hear it unless you open the door. Turned it on again after this fix and basked in the warmth again. Then I turned on the engine room blowers and cracked a saloon window and watched the engine room temp rise. I'm really looking forward to this feature next winter -

Yeah, should have done it this way first. I simply had no idea of the intensity of the heat shooting out of these things. But now I do and it's properly managed -

 

[jtdums]

Watch the temperature on that exhaust extension piece both for proximity to the hull and the mount to the wood ladder.

My piping and muffler needed standoffs because of the heat generated. Unit works great, and like you said really produces a great deal of heat.

 

[Delta Riverat]

Oh yeah. Part of the reason I was not expecting it was all those you tubes with folks just standing or sitting in front of the output pipe. I don't want to be any closer than 4 feet. The exhaust is air spaced whole length, the only 2 contacts are the through hull and the pipe to the ladder which is spaced with a 1/4" nut. The temp of the pipe at the end is touchable unlike the muffler.

 

[Delta Riverat]

One last update. I did an exhaust improvement, added a standoff for the muffler. Now the outside is secured by 2 screws as well as the 90 degree slip on elbow. No more bendy;

Also found out during this operation that my controller is one of those H1 to H6 units as well as the fact that the ECU's are specific to the controllers and these models are getting hard to find so I ordered up a spare. Seventy five bucks shipped. Amazing.

Anyway, this has been a rewarding project. Got to the boat today and switched to "Alpine Mode" which supplies less fuel and linked the remote fob and turned the sucker on with the remote. Twenty minutes later the boat was nice and toasty so I took my shirt off -

 

[Bmarler]

Good deal, nice to have heat!

 

[Delta Riverat]

And now I even have a spare.

The back up heater kit arrived today in perfect condition and has the same (H1 to H6) controller that is installed. So I got a complete spare parts kit for $76 -

 

[paulga]

Three pipes fitted;

Had to locate the unit first with one pipe and mark it on the shelf and then it all seemed to fall together;

Now on to the fuel line.

could you paste a link to the combustion air intake through hull fitting?
also, what is the red tint inside the hole for the exhaust through hull? this tint was not seen in post #47

 

[Delta Riverat]

Sure, here it is.

The red color is the sun lighting up the fiberglass shell.

 

[paulga]

is there requirement on the min clearance, vertical/horizontal, bet the combustion air intake and exhaust vent, and bet the engine room vent and exhaust vent?
any requirement on the max combustion air intake hose?

 

[Delta Riverat]

Don't know about clearances, but I would keep the combustion air intake as short as possible, under 1 meter for sure.

Today I brought my temp meter and my CO meter and verified a good install. Set at max on "Alpine Mode" the pump runs at 4 Hz, about .1 mL fuel per second or 360 mL/hour. Air temp on output was 190F, exchanger was running at 175C, no CO from the heater output and a max of 6 ppm out the exhaust.

A nice clean burn -

Closet temp was 90F and ambient was 65F. I'm feeling real good about this project.

 

[boomerang]

I've been casually following this thread since a diesel heater is slated to be installed on our boat too (after we chisel away at some other ,more pressing projects this year). You've done a nice job and used some ingenuity regarding the layout and installation of the system and I hate to sound like your typical know-it-all forum pundit but that exhaust stack sticking straight up into the air just looks like it's inviting a system full of water next time it rains or the boat gets washed!

 

[twistedtree]

Is the exhaust outlet facing up and can rain get into it?

Also, how hot does all that metal work get? Any burn hazards?

 

[Delta Riverat]

The entire external exhaust is air spaced off the wood / GRP and it gets pretty hot say 300F, but the wood / GRP only warm (finger touch easy) It will burn you if you touch the metal, but if it's cold enough to be running the heater you probably won't want to be spending much time on the aft deck anyway. Yes exhaust pointing at sky but under Bimini.

The muffler has a drain hole in the bottom, any water in should drain there. This hole is there to drain condensation but I've not seen any so far with over 6 hours of operation. The intake and exhaust can be plugged for washing also. During the warm months, the whole thing can be removed and stowed by removing 2 screws.

 

[twistedtree]

The entire external exhaust is air spaced off the wood / GRP and it gets pretty hot say 300F, but the wood / GRP only warm (finger touch easy) It will burn you if you touch the metal, but if it's cold enough to be running the heater you probably won't want to be spending much time on the aft deck anyway. Yes exhaust pointing at sky but under Bimini.

The muffler has a drain hole in the bottom, any water in should drain there. This hole is there to drain condensation but I've not seen any so far with over 6 hours of operation. The intake and exhaust can be plugged for washing also. During the warm months, the whole thing can be removed and stowed by removing 2 screws.

thanks.

 

[Delta Riverat]

Today I experimented with the John McK double Chinese straight through muffler set. Because I had another muffler in my "spare parts kit" for free!

It does work well, noise is less and the look is a little cleaner too me thinks as compared with the wrinkled pipe. I also found that 3/4" copper pipe fits nice inside the the muffler ends.

A bonus was fitting the SS elbow on the intake just in case it does rain hard. I would be more concerned with sucking rain in the intake vs have it boil off or drain out the exhaust. It is not secured, just pushed in and easily removed and stowed.

Best of all, the setup ran fine as verified with temp and CO meters.

 

[Delta Riverat]

Here is the final version;

Two 1.5" spacers, close coupled mufflers connected by 3/4" copper pipe and 45 degree street elbow outlet. Keeps hot exhaust gas away from tank, ladder and boat. That intake elbow really helps with the noise as well as protecting the intake from unwanted elements. I've been getting good use from it too, more than I thought as it's been chilly this year so far.