Which multi-fuel heater for this application?

[jesusgatos]

I've got a propane-fired tankless water heater that I'm going to use to heat my M109. I'll be running glycol/anti-freeze in a closed-loop to provide radiant heat (routed 1/2" PEX tubing throughout the floor in the box), as well a few forced-air heaters/heat exchangers. There will also be a heat exchanger that will me to use the engine coolant as an alternate heat source.

But the theme of this project is OVERKILL, so I'd like to build-in backups for backups wherever possible/practical. I'd like to install a multi-fuel heater, but the question is - which one? I've seen them mounted on the fender, and under the dash on the passenger's side, but I've also built a cabover rack (link to picture - that big white box is a Reddot AC compressor), where I could mount a heater that might not fit in either of those other places. Although everything I've heard about those multi-fuel heaters is that if anything, they put out TOO MUCH HEAT. So I don't know if I really need anything bigger than the standard multi-fuel heaters, but I know there are even a few different types of those. Can you guys please help me figure out what my options are, so I can make an informed decision about which one I should use for this application.

 

[gimpyrobb]

I would look for the fuel fired coolant heater. That way you can have the motor warm when you star it and heat the water for the radiant floors too. I have pics of one in my photo album. Let me know if you need more info on it.

 

[jesusgatos]

That sounds like a GREAT option. Also means I wouldn't have to install any additional ducting in the box. Tell me more. Is there a military forced-air heat exchanger that I can plumb into that and use in the cab, or should I plan on figuring something else out? Can the coolant heaters be used while the vehicle is in motion, or they only for pre-heating? What's up with your combined heater controls?

 

[gimpyrobb]

The set I have is meant to go in a cucv. I have yet to get off my azz and install it. I don't think you are supposed to use it while the motor is running, but you could install some valves to turn the ports for the motor off and just heat the radient coolant. The only hot air comming from the unit would be exhaust, I don't think you want that in living space, I think the military ducted the exhaust to the oil pan to warm the oil in cold cilmates. The multifuel hot air unit is available as another unit, but if the motor is warm, just use a regular heater that uses hot water for heat.

 

[jesusgatos]

I was thinking about the multi-fuel hot-air, but the multi-fuel coolan heater might be a good option too. Gotta think about this a little bit more, but I tend to get a little carried away with this kind of stuff. Right now I'm wondering if I have enough room for both of them...

 

[deuceaid]

Any pictures of the multi fuel coolant heater?

 

[gimpyrobb]

http://www.steelsoldiers.com/members/gimpyrobb-albums-gimp-s-pics-picture1458-coolant-heater2.html

This is one of our members here. Different heater, same function. Dunno if it comes with a controller and the other accessorys.

Southwind Coolant Heater Diesel Fired 15K BTU Military:eBay Motors (item 120500036774 end time Dec-10-09 08:17:43 PST)

 

[dk8019]

Jesusgatos,

Those are some of my coolant heaters, if you want one just PM me, I'll give you a much better deal than the ebay price, my wife would like them out of the closet

 

[jesusgatos]

Thanks for posting! I'm definitely interested. How does the model you have compare to Gimpy's? Is it diesel-only, or multi-fuel? Do those heaters have the wick, or are they the ceramic ones? Do you have any controllers or other stuff I might need to install/use it? Sorry for all the questions, I just don't really know what I'm getting into...

 

[cranetruck]

Jesse, the Stewart Warner unit (dk8019's) uses a wick, don't know about gimpy's, but it looks like a Benmar model and in which case it will have a ceramic vaporizer (no wick).
They are both "multifuel".

 

[dk8019]

Crane nailed it, right now I just have the heaters themselves, no control boxes

The boxes aren't too hard to locate, I have a few for future projects sitting around.

 

[jesusgatos]

Sweet! That's what I was hoping to hear. Thanks Cranetruck. PM coming your way dk8019...

 

[jesusgatos]

So, what do you guys think about using one of these as an alternative heat source for the radiant heating that I've built into the floor of my M109 motorhome conversion? I've got a propane-fired tankless water heater that I'm planning to use as the main heat source, and I'm planning on making some type of heat exchanger that will connect the radiant loop with the engine's coolant system so that I can pre-heat the engine or heat the box while the engine is running, but I like the idea of having a multi-fuel fired backup.

And... would I be crazy to wonder whether I might be able to use another one to heat fresh water for cooking and showering and whatnot?

Do any of you know how much these heaters will increase the temperature of water/coolant in a single pass? Also wondering about the efficiency of these units.

 

[jesusgatos]

I got two of those heaters, thinking that I'm definitely going to use at least one of them.

Question: How are these things meant to be mounted? I mean, I know they were mounted in the engine compartment, but to what, and where? The heaters I got don't have any mounting brackets or anything. If mounts are available, I'd like to try and find some. If I need to make them, I'd like to know what the stock mounts looked like. Thanks.

 

[cranetruck]

Here are two typical mounting arrangements, they are held with hose clamps onto cradle like feet, if that makes any sense. The parts manuals will show the items needed.
Most of your other questions should be answered in the article in the Feb 2010 MVM issue.

 

[ODdave]

DK8019, do you have any more of the coolant heaters? im very interested, Thanks, -Dave-