Eberspacher B3LC

[djw]

Any suggestions on debugging my Eberspacher B3LC heater that does not now seem to want to fire, but electrically seems to work fine? It seems to be in flawless condition save for the fact that it doesn't seem to light.

I have not fiddled with this much but I am almost certain that I tested it in the spring and it worked fine.

The owner's manual mentions something about if it fails to fire so many times it goes into some sort of a "fault mode" (and I am not sure how to get it un-faulted to retry).

As this heater seems to have an equivalent Espar, Airtronic, Webasto version, it would seem there is some experience or solutions available for diagnosis.

Thanks.

[djw]

I surmise only the Austrian refurbished trucks got the B3LC Eberspacher made in the mid 90s. Since everything electrical seemed to function fine and the glow plug heated, the fault turned out to be fuel delivery.

Don't know about the old BN4 heaters that are more common, but the B3LC has a tiny metering pump that is electrically pulse controlled which lives behind a a debris shield in the upper right hand wheel well beside the fuel tank. The connecting hoses had gone porous and the intake side of the pump was sucking air unable to push fuel to the heater. Replacing these two short jumper hoses with new and a few clamps, the heater fires right up. The metering pump only pushes a tiny amount of fuel at almost no pressure with each pulse but the heater controller changes its rate on demand.

The pump can be serviced (not documented in the Eberspacher manuals) and is ridiculously expensive ($300+) if you can find one at all (Eberspacher pn 25.1831.45.00.00). They are not interchangeable with similar models because the are adjusted to deliver the specific rate at the factory for the heater model. The intake end can be cleaned, there is a small screen under the fitting. The other end controls the fuel metering.

Hope this helps the handful of Austrian K model owners that are fitted with this heater. These heaters do not appear to have a lock out on fail function contrary to what the manual says.

These two sites are a wealth of information for debugging heater operations. Kudos to the authors as the information is quite hard to find from Eberspacher.

http://www.nomadic-one.com/reflect/eber ... er-trouble

http://www.letonkinoisvarnish.co.uk/Ebe ... tro_1.html