Mahe 36: Diesel heater

[Rufduck]

Greetings,
My new 2007 Mahe 36 Duo is now home at her dock in the Pacific Northwest of the US. In reading the many Mahe posts, it seems that many if not most of these boats are cruising in warm climates. One World will be sailing year round up here and to my joy came equipped apparently with my a factory installed Eberspacher Airtronic D4 forced air diesel heater. Am very familiar with these, having installed several. To my sorrow, there is no power to the temperature/start module. Almost certainly the inline fuse.
I've looked everywhere for the necessary inline fuse and for the fuel metering pump for that matter with no luck. I hate to start cutting the wire looms apart to track where the power leads separate from the rest of the bundle. As there are really only two things with these that can be problematic, the pump and the fuse, they should be in an accessible location...SO.
Any ideas anyone?
Cheers, rufduck

[Paul L]

Have you found the breaker for the main unit?

[Rufduck]

There should be no breaker in the circuit. Only the inline fuse and it should be within a few inches of where it taps power.
The information is pretty explicit about not switching off power before the unit cycles through its programmed shutdown sequence. Doing so can damage its little brain hence no switch or breaker to inadvertently throw. Just push the "off" button on the temperature module.
To answer your question in another way, I have not found where it tarps into the 12v system. Nor where it taps into the fuel system.
Cheers, rufduck

[Paul L]

I guess it is time to start tracing the wires then. The system has to be using decent size cabling, as they use a lot of startup current on the glow plug. No matter what the manufacturer sez, I would not install one without a breaker. I want to easily be able to isolate the unit if something happened.

[Rufduck]

An update for anyone interested.
I found the fuel pump for the heater...by accident.
I wondered if by chance I missed it in the area behind the access port at the helm station where the fuel shutoff valves are located.
I found the pickup tube and tank fitting and then found the fuel gauge sending unit. Between the two terminals was a hose with metal bands which didn't look too proper, so I gently lifted it off and there was the pump, loose on top of the tank. It is designed to be precisely installed at an angle in a rubber isolation mount. It is neither accessible for servicing nor installed properly..

Does anyone know if there is a way I can find out what a given hull number was originally equipped with? If this was factory installed and it appears to be so, I am dismayed at an utter disregard for workmanship and follow up quality control.
The primary power leads are supposed to be fused to 25 amps according to the installation instructions and appear to run all the way from starboard to port so a big brown and red pair of wires should be pretty easy to trace.
Will let you know what I find.
Martyn

[Stu Jackson]

Wire looms are a device of the devil. I am SO glad I don't have them. NONE

Good luck in tracing. Label, of course, as you go. Good luck.

[Scott Berg]

For those fighting wire looms a TDA (Time Domain Reflectometer) will tell exactly where in the loom the fault (short, open, damaged conductor) is. The price has come down and many good marine electricians have them now. When all else fails ask to borrow one from a friend; I couldn't do my job without mine. Example: https://www.instrumart.com/products/...-reflectometer

[Rufduck]

Update. I found the fuse block for the heater. It was tucked behind a bundle of wire looms,sandwiched between the looms and the heating duct and securely wiretied in place in the starboard engine bay above, behind and inboard of the rudder tie rod. It is 10 feet from the house bank and may tap power from one of the 2 12v breakers in the port engine bay.

Both fuses are sound so will slap a voltmeter on it to see if it is hot. If not I will make a test jumper and try to fire off the heater.

Cheers, Martyn

[Rufduck]

Well, the mystery of the Espar (Eberspacher actually) D4 heater has ended, happily sort of.
I finally threw in the towel and hired a local Espar guru. I explained the tests and results I had done and after a number of minutes of fruitless searching said he would track the power leads to their source.
After locating the red lead on the opposite side of the boat, he held up the negative wire and announced that it was not hooked up. Seems I had some work done before I left Grenada and the fellows unhooked the negative lead to better access the structure and failed to hook it back up.
After at least two years sitting idle it started up and ran like a charm.

Contrary to the installation instructions, power was tapped at the common breaker to the rest of the 12v systems.
I have resecurred all wires and ducts and separated the wires from the ducts.
Cheers, Martyn