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Old 01-19-2014, 04:33 PM   #6
Aqua Puttana
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Default Re: Some 2004 Espar Heater Notes

I believe that now I have enough information to end my recent obsession with all things Espar in my 2004. (Just my latest obsession of many?)

The Booster heater is working fine. It is wired to pre-heat the engine. I know what specific burner part number will work.

There was one site that I found which seems to have really good information for the 2004 year range Espar heaters. Unfortunately it is in German and I'm not fluent at all. It does have some great pictures for showing the differences between the non-fuel strainer burner with integral fuel pipe (as I have) and the similar, but quite different design fuel strainer style burner.

I've since learned that Google translate does a rather quick and good job for segments of the German text.

This is the blower assembly with integral fuel pipe. (Similar to my 2004.)

Note the Ignition Air Duct or Channel. On my heater that was completely blocked. It almost seemed like a compound rather than just dirt. That might explain that my heater is in such good condition by having not operated since new. That air duct is critical to igniting the heater. In hindsight, I should have just cleared that duct, cleaned the burner "D" glow chamber with carburetor cleaner (as opposed to digging at the soot/carbon build-up with picking tools - screwing up the screen), and lastly run a fine wire into the fuel pipe with a carb cleaner flush. I'm convinced that would have restored my heater to operation. I base that on the fact that, except repairing the self-inflicted damage to my burner screen "wick", all that I did was to clean my heater fuel and air passages for the heater to work properly.


The Burner with Integral Fuel Pipe

Note that the fuel pipe is sandwiched between the blower and burner faces and recesses into the Blower Fuel Pipe Channel shown above.


The Fuel Pipe Glow Plug Holder Assembly.

The fuel pipe comes up on the opposite side of the blower assembly as compared to the integral fuel pipe burner style. The fuel pipe is not sandwiched between the blower face and burner face.

It also includes a cylindrical Fuel Strainer assembly aka Fuel Screen aka Glow Pin Screen aka Atomizing Screen.


The Strainer Type Blower Assembly. Note the Ignition Air Duct which is similar design to mine that I found plugged.


The Fuel Strainer Type Burner Assembly. The 2 ea. green O-rings seal the Fuel Strainer. This uses the "stepped" strainer style. The "D" Glow Pin Chamber also includes a Screen "Wick" even with the Fuel Strainer.


A note for cleaning the Fuel Strainer type burner.

The back curved walls area of my integral fuel pipe Burner Burner 25 1922 10 00 00 "D" shaped glow pin chamber is a solid piece. Based upon visual inspection the brand new Fuel Strainer type Burner 25.2216.10.0000 aka stamped 25 2149 10 00 02 also has a solid back curved wall. I inspected the brand new Fuel Strainer glow plug chamber. Unfortunately I can't get a good picture inside so I'll describe it as best I can.

Refer to the 2nd burner picture in post #2 above for an idea of the screen and 3/16" hole position.

The Fuel Strainer burner is non-magnetic and appears to be stainless steel. The back curved walls area of the "D" glow pin chamber is solid. The flat wall has a screen embedded to it on the inside (in the glow pin chamber). An approximately 3/16" hole is in the flat wall out into an intermediate chamber. The screen surrounds that hole, but doesn't cover it. The screen disappears into a slot at the top of the "D" chamber flat wall. There are no other holes which I can see other than the tightly filled screen slot and 3/16" hole out to the intermediate chamber.

My cleaning suggestion applies to the Fuel Strainer burner the same as the integral fuel pipe style. It is best to rely on solvents like carburetor cleaner and avoid poking around too much. The screen attached to the wall may need cleaning, but you don't want to disturb it too much.

The two different fuel pipe entries leaves me a bit unsure as to actual primary ignition. I know that the screen/slot "wick" design is critical for both burner styles. It is interesting that the integral fuel pipe disappears behind the "D" chamber at the rear in contrast to the Fuel Strainer fuel pipe metering fuel into the "D" chamber from the front or glow plug end. I'm convinced that the glow plug produced flame ignites the fuel and exits thru the 3/16" hole into the intermediate chamber. The upstream air pressure via the Ignition Air Duct (Kanal) should overcome the larger downstream air opening (less pressure) so that the glow chamber flame moves out into the intermediate burner chamber. That same Ignition Air Duct air flow must also carry the fuel out to the glow plug chamber in any burner which has the Fuel Strainer. The heaters can be mounted in various orientations so the fuel isn't just gravity fed.

Anyway, things need to be clean and open enough, but not open too much, for flow. I know that the screen and slot, the Ignition Air Duct, fuel pipe, strainer, etc. needs to be clean enough for the heater to work.

The German language site is here. My appreciation and thanks goes to the originator. (Pretty much for the pictures, because I couldn't decipher the technical language. )

There are also some motor brush modification pictoral tips here. The pump motor/brushes shown are very similar to the Sprinter motor, but not the pump body that is shown.
(The 2nd time that I changed the brushes on my water pump I used tape style dental floss to hold the brushes away for assembly. Someone on Sprinter-source mentioned that trick. It worked great.)

The Espar heaters are pretty basic as to the mechanicals and theory. I am impressed with the simple, yet effective design. Once the diesel fuel is ignited, the metered fuel flows in kinda like an old kerosene pot stove with a carburetor. Once lit the diesel fuel will continue to burn readily.

I've not had problems with the control. I suspect that the control module is not at all repairable. There have been some pictures of corroded wiring including one in the German site so that condition is worth watching for.

Note: One expert I've communicated with warned that Bio-fuel is a problem with the Espar heaters. He even cautions against 5% and suggests installing a "Day Tank" and running the heaters on Kerosene. I can't disagree, but installing a day tank with easy fill capability is likely easier said than done. He mentioned that a coffee colored residue which is harder to clean than the normal black soot is one evidence of bio-fuel rlated problems.

Fitting a day tank with an external fill capability may be easier than I thought. Opposite the OEM fuel fill (passenger side) there is an identical unused sheetmetal chamber which could be used to install an external day tank fill point.

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Last edited by Aqua Puttana; 02-25-2017 at 02:41 PM.
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