I had the same experience with my D5 as you. In fact my second failure. To answer your question about the ventilation function first, the flow into the salon cabin is OK but poor in the fore and aft cabins. I have fitted Cafranio Sirocco fans to overcome
this problem. They are stylish, quiet, efficient and have a timer function which allows you to run them for 2,4,6 or 8 hours then switch off. I set my cabin fan to run for two hours when I go to bed.
Regarding your Eberspacher D5, this link is useful when trouble shooting:
The hard rubber knob on my control unit failed, and like so many scams these days, you can't buy a spare without buying the whole switch! As the diagnostic controller costs not much more, I replaced my controller with one. This was most helpful in trouble
shooting, as was swapping the ECU and current limiter with Bootlegger, another Amel SM2K that wintered next to me in Cyprus. The diagnostic controller also allows you to reset a locked out ECU.
My first failure was an ECU -expensive! The second was like yours. Everything seemed dead. The diagnostics controller gave an error code suggesting a problem with the blower. When the D5 is first switched on it goes through a 3 second self diagnostic routine
which tests the fuel pump, the blower and the glow plug. If you remove the inlet air duct on the aft end of the unit and have someone watch, the blower fan should kick during this test. You should also hear a relay operate. If you hear nothing, then I would
suggest the problem may lie with the ECU. I heard the relays OK and when I put a direct feed onto the bower motor, it ran normally.
This narrowed it down to a small PCB that slides into the side of the heater unit near the aft end. This board controls the power feed to the blower and the glow plug. This board is easily removed but take care in lifting the connector plugs off the board
as the pins are weakly soldered to the board. I broke one of the pins and had to fabricate a new one. This board is easy to troubleshoot and I found that a track that looked perfectly normal was in fact open circuit. There was an invisible break where the
track went through a right angle. Soldering a small piece of hook up wire over the fault restored my unit to full working order.
Like you, I probably don't use the heater that often, but I do like everything on board to work as it should.
Best of luck.
Ian Shepherd SM2K 414 (2003) Crusader - Larnaca Cyprus.
My boat has the Eberspacher D5 diesel heater...which does not work.
I got to thinking about it since lately it would be great to have the "fresh air ventilation" setting functional so we could circulate fresh air from outside to inside. This is especially needed during nights with little breeze to bring the cool evening
air down below.
Before I go to the trouble of trying to figure out what's wrong with it, does anyone use it for fresh air ventilation? Does it help reduce the temperature in the boat when the outside air temp is lower than inside? i.e., does it move enough air to be helpful?
The other approach I'm considering is to mount a fan on the aft cabin hatch to exhaust air from the boat. 24 volt fans meant to cool the radiator on semi trucks are available and have sealed motors. I'm sure there are other ways to skin the cat...any suggestions?