Diesel Air Heater

[Hiyu]

Just installed this puppy and I can tell you, it's gonna keep us warm and toast in any temp! It's the 8kw version.

It did not come with a filter so I improvised, I moved the pump to the outside of the unit on the back, just reversed the rubber mounting bracket, drilled a hole for the fuel tube to exit the shell, at that point installed the filter then pigtailed it back to the exterior fuel pump. Had to notch out on the upper corner for the fuel line returning to the burner unit, protected it with clear vinyl hose. The pump is a bit noisy, I will encase it with sound proofing material. No matter what, it's worth the noise to get this heat. Pictures attached. I have two marine deep cycle batteries in parallel for boondocking purposes. Installed the PD 4100 power converter unit, totally pleased with what it can do.

[Iceni John]

I bought two Warmtoo metal-case "8kW" (actually 5kW) heaters and installed one for the bedroom; the other will eventually be for the front if the bus. It's mounted on its side* in the bathroom next to the bedroom, and blows hot air through the bathroom wall straight at the bed; doing it this way also means that its exhaust is a straight run of just a few feet through a hefty stainless pipe that goes through the bus's side wall, and no duct is needed for the hot air outlet. The one thing I spent some time to make is two transfer pumps that suck diesel out of the bus's main tank and push it to each heater's day tank, then I can easily top up each day tank when needed. The heater I installed works excellently, but I did tweak its fuel/air setting to make it burn slightly cleaner when I'm at higher elevations. So far, so good. They definitely get a thumb's up from me.

John

* Yes, the glow plug is still uppermost!

[Peterjk]

Originally Posted by WIbluebird

Do both air heaters use the same tank tap?

Did you retain the stock fuel pump for the one in the back of the bus? I already have one air heater in the front of my bus but I'm curious if I add another one whether the fuel pump will be able to push it 20 feet to the heater in the rear.

Both fuel pumps are stock. The length of both fuel lines are about 5 foot each using very stiff fuel lines, not the soft fuel line they sell them with. The location of my heaters are front one is boxed in on the back of the front wheel well. Fuel tank [15gal] is in a central area between them outside. The back heater is on the front of the rear wheel well. So in your case I doubt 20 feet will work. I went w a separate heater tank, as I didn't want to mess w the bus tank. https://www.skoolie.net/forums/membe...lbums1998.html

[o1marc]

Originally Posted by Peterjk

Both fuel pumps are stock. The length of both fuel lines are about 5 foot each using very stiff fuel lines, not the soft fuel line they sell them with. The location of my heaters are front one is boxed in on the back of the front wheel well. Fuel tank [15gal] is in a central area between them outside. The back heater is on the front of the rear wheel well. So in your case I doubt 20 feet will work. I went w a separate heater tank, as I didn't want to mess w the bus tank. https://www.skoolie.net/forums/membe...lbums1998.html

I was fussing about plumbing mine into the bus, I like the idea of a separate tank for the heater. Much easier to plumb.

[cadillackid]

20 feet is a long way.. these pumps arent pressure pumps.. these pumps are dosing pumps.. they dose out a specific amount of fuel.. there can also be air bubbles mixed with the fuel.. air is compressable so 20 feet is a long distance.. depending on how your line runs, you may be able to locate the pump closer to the heater and pull the fuel.. dont use the same tap unless you have a check-valve someplace. . otherwise you can suck fuel from the other heater even if its not running.. i dont know if they have built in check valves or not.. I tend to think not since its recommended the pumps are installed at an angle, it creates a trap , the pump itself likely has some check properties but ive never played with them to know if the opumps will check flow enough you can use a dual tap or not.. I would personally only run one heater per tap..

[WIbluebird]

Installing a seperate diesel tank when you already have one on board seems redundant and an excessive amount of work to keep full....As long as you aren't tapping into the bus engine fuel lines then there should be ZERO issue with tapping into the main tank.

My bus had 2 un used taps. All I had to do was unscrew the 3/4 inch nut and cover off and drill a tap in that.

I might play around with a single pump design that forks off after the output....I'll have to see what the chinese heater facebook groups say (they are surprisingly a good source of info unlike the skoolie ones).

[cadillackid]

Going off the main tank absolutely makes sense.. on mine I set the heater pull a few inches above the engine pull so an accidentally left-on heater can’t run the bus out of fuel.

A single pump would be an interesting thought . Not sure how that would work and not make the dosing go Wierd. The dosing pumps aren’t designed to have positive pressure behind them . Someplace I’ve seen a video done on positive pressure behind a dosing pump caused it to over fuel the heater. I’m sure you prob have watched David’s YouTube videos on how the pumps work and that each one has a value as far as the amount of fuel it doses with each click.

[Rwnielsen]

I have a separate, 70 gallon, diesel tank just for the generator(s). I have 2 diesel heaters. I was going to run one fuel line from the tank and `T` it off off through 2 check valves to the heaters. As I recall someone here cautioned me against that idea because the pumps may not be able to overcome the resistance of the check valves. I'll be installing one of the heaters fairly soon so I can keep working on the bus when it cools down outside. Should I just run two lines independently or no?

[Peterjk]

Originally Posted by Rwnielsen

I have a separate, 70 gallon, diesel tank just for the generator(s). I have 2 diesel heaters. I was going to run one fuel line from the tank and `T` it off off through 2 check valves to the heaters. As I recall someone here cautioned me against that idea because the pumps may not be able to overcome the resistance of the check valves. I'll be installing one of the heaters fairly soon so I can keep working on the bus when it cools down outside. Should I just run two lines independently or no?

I ran 2 separate lines in my case. Reason, I can maintain a line or heater without impacting the other heater, as they are independent. I like a little redundancy for important things esp heat, Im near Chicago so it gets cold. They are also filtered at the tank independently. Lastly if you ever have any issues, I would say troubleshooting will be much easier as you will have another heater and line to compare to. Recommended educational videos by this gentleman: https://youtu.be/tvwmU_CcmGI He has a very long video about fuel lines worth watching.

[Rwnielsen]

Originally Posted by Peterjk

I ran 2 separate lines in my case. Reason, I can maintain a line or heater without impacting the other heater, as they are independent. I like a little redundancy for important things esp heat, Im near Chicago so it gets cold. They are also filtered at the tank independently. Lastly if you ever have any issues, I would say troubleshooting will be much easier as you will have another heater and line to compare to. Recommended educational videos by this gentleman: https://youtu.be/tvwmU_CcmGI He has a very long video about fuel lines worth watching.

Thanks for the link, I'll be watching that shortly.

[Peterjk]

Originally Posted by WIbluebird

Do both air heaters use the same tank tap?

Did you retain the stock fuel pump for the one in the back of the bus? I already have one air heater in the front of my bus but I'm curious if I add another one whether the fuel pump will be able to push it 20 feet to the heater in the rear.

Separate fuel taps.
Stock fuel pumps.
20 feet won't work.

[cadillackid]

everything im reading says 20 feet ias doable as loing as the pump is in the middle.. I read back oin the instructions for my real webasto. . and then asked the question of D&E. (where my chinese coolant heater came from).. and both say 2 meters max from tank to pump, and 5 meters max from pump to heater...



pump should be at an angle upward from 15-45 degrees and fuel line should be as striaght and level of path as possible. (ie dont create a lot of hills and valleys in your line)..

[Peterjk]

Originally Posted by cadillackid

everything im reading says 20 feet ias doable as loing as the pump is in the middle.. I read back oin the instructions for my real webasto. . and then asked the question of D&E. (where my chinese coolant heater came from).. and both say 2 meters max from tank to pump, and 5 meters max from pump to heater...

pump should be at an angle upward from 15-45 degrees and fuel line should be as striaght and level of path as possible. (ie dont create a lot of hills and valleys in your line)..

2 meters max from tank to pump sounds right and is a reasonable distance.

You can probably push these little pumps to greater distances. BUT, the trade of will be their ultimate life span, meaning, longer distance, shorter life span.


Today, I spent the day insulating my 2 diesel heater fuel lines. I purchased rubber fuel line, and placed the stiff diesel lines inside of the rubber lines. So now there is at least a second barrier and the fuel lines are not exposed under the bus .

[cadillackid]

great idea on the outer fuel line!.. also helps to keep them from bending and curling everywhwere!..

[Rwnielsen]

Originally Posted by Peterjk

Recommended educational videos by this gentleman: https://youtu.be/tvwmU_CcmGI He has a very long video about fuel lines worth watching.

I watched all 11 of his videos. Fortunately I bought a decent pair of heaters, purely by accident. I now have a much better understanding of how they work and what to look for if they don't.
Thanks again for the link

[Iceni John]

Because most of these CDHs' instruction manuals are laughably-translated gibberish and gobbledygook Chinglish, it's best to read the original Eberspächer manuals from Germany. They precisely specify, as Germans so like to do, exactly how any Eberspächer-clone heater should be installed. Follow those directions to the letter, and you won't go wrong. Here's one manual: https://www.butlertechnik.com/downlo...cal_Manual.pdf

The good folk on the FaceBook CDH forum are, for the most part, quite helpful and sensible, and they have seen and heard of pretty much any possible failure and its reasons. It's well worth perusing that forum and its library of technical information and resources.

John

[LargeMargeInBaja]

Originally Posted by Chess

...wood stove...back bedroom area got cold while my kids upper bunks were too hot. My middle section...

.
After several linear conversions including a 30' semi trailer and a 30' bus with a central heat-source, we realized a squarer shape distributes heat efficiently compared to a long narrow shape.
.
Our THOW is three paces across by seven paces long.
Part of the long dimension is blocked by storage, so heat tends to stay in the occupied zone.
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We heat with a single Wave 3 catalyst rated 1,700/3,000Btu using propane.
On 'low', that little heater is a roaster!
We temper its tendency to scorch the interior by further opening at least one window... from our standard quarter-inch to an inch.
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To reduce condensation, we open at least two windows on opposite walls.
Leaving for the day, we open all the windows, hoping the air exchange carries moisture outside.
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An aside:
During warm season, we use fans, portable Craftsman 20v battery-operated.
Could a couple tiny fans help distribute your heat?

[cadillackid]

air circulation is a must... at mty parents house the main living room with the wood stove gets cra cra hot while even the rooms next to it are chill and upstairs.. we installed Cold air returns on the high part od the wall near the stove.. turn on the furnace fan and it sucks in that hot air from the ciling and pushes it out the various registers on that floor of the house.. made a huge difference

[LargeMargeInBaja]

Originally Posted by cadillackid

...air circulation is a must... at my parents house the main living room with the wood stove gets...hot while...rooms next to it are chill...

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Based on my experience with a main-room wood-burning stove, the combustion pulls 'room air' up the chimney.
The rising 'chimney air' creates a vacuum; that escaping air must be replaced.
Distal rooms -- bedroom, bathroom -- inevitably are colder because they leak cold outside air around windows and vents... pulled at a fierce velocity by that chimney air.
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I think a better way uses a dedicated duct, bringing outside air directly to the stove combustion-chamber, then that air goes up the chimney.
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My motto:
* SIMPLER is BETTER.
If I can accomplish the goal without complicated machinery or procedures, I did my part... time for a well-deserved nap!

[cadillackid]

the fireplace in my house has a combustion air inlet so it doesnt use house air for the fire... theres a heat exchanger in it to replace some of the heat.. im sure some air gets sucked in by venturi effect since i burn the fire with the doors open but the air intake aims to stop some of that...



im a big proponent of outside combustion air specifically for that purpose.. in the case of my parents house the stove is on an inside wall and right below it in the basement is the furnace for that floor.. so running a duct up the wall was the simple thing to do...



do they make wood stoves that have a ducted air intake where you can pipe in your own combustion air?