My old Webasto HL 3003 heater decides highly itself to what extent it wants to function. Coal (armature) it consumes a lot of, and it also has happened, that the relay, controlling the hole burner system, fails. For some reason the printed circuit board emits a sticky substance, which become fixed all over inside the relay box. In worst case it causes to happen, that the relays, mounted on the print, fails to function. For example that the engine, at a state where to stop, keep turning on. Below a photo of the electronic unit in question "Steuergerät SG 1544/24V".
If the unit is separated at the bottom, the print circuit board can be pulled out, shown below. The four relays is seen at the bottom of the print circuit. Number 1 from the left closes when the burner is put on, number 2 closes the engine, and is the one causing my engine to keep on running, even if it should stop.
Clean the surface between the armature and the plate thoroughly with a cloth soaked in benzine, then at least this problem has been solved. The switches itself can also be tied, clean them as well, but be careful not damaging the parts.
Put the print board back into the box, and seal it with tape to avoid moisture to penetrate into the box.
02.2004.
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