Mastervolt Hull Isolation Control - meaning of lights

[nicholasdrayer]

Hi all,
I have 3 MasterVolt "Hull Isolation Control" C-4-HI panels on my (new to me) aluminium yacht, for 24v, 12v, and for 230v.


Could someone tell me the meaning of the lights? I have the 'installation manual' which says nothing regarding the operation. So currently when the button is activated on each 3:


12v push button - Negative lights bright, Positive stays off
24v toggle button - Negative lights bright, Positive stays off
230v push button - Both lights identical, both not-so-bright


I have a vague feeling based on the wiring diagram, that both lights should be shining brightly. I'd really like someone to confirm for me!


Thanks for reading!

Nicholas
SV Fenna

[nicholasdrayer]

Well, nobody seems to know the answer :-(. For anyone looking at this in the future, I am now, after some spelunking with my multimeter, fairly sure that the Hull Isolation Control lights should present both lights identically, medium brightness. And in my case, the two where the negative light is bright, it means the negative battery pole is connected to the hull.
I am now in the process of finding out where the problem lies. But that's another topic.

[skipperpete]

I’ve only encountered the less complicated push button 2 light version and I don’t envy you having to search for the DC leak. I repowered a number of French built alloy hulled yachts with various 4JH Yanmar engines when the original Volvo MD 22 and Nanni engines failed and since Yanmar don’t sell an “off the shelf” insulated earth engine I had to convert them….. not as easy as it might seem but after a bit of a learning period I managed to keep those pesky “leakage warning lights” dark. Fortunately the French do a good job of wiring the hull above ground so only the engine harness, components and control cables were my concern. One had the push button 2 light panel but mostly they used an unbranded panel and my own boat just had a red and green light, no switch or panel. The French builders wire in a negative buss where all the -ve cables return to so troubleshooting is fairly easy by just disconnecting one wire at a time from the busbar until you get a safe reading …. Then you get to follow that wire to its component to work out how it managed to contact the hull. Good luck with the tracing and apologies for not being helpful with advice about your particular mastervolt detector.

[nicholasdrayer]

Thank you for the kind words, Pete. For both the generator and the main engine, there's no contact between each of their starter battery poles and the hull. But the negative of the house bank and hull is about 9 ohms. So I'm putting my money on the house bank's wiring. Although it's a puzzle to find the problem, it'll surely be easier to solve than with the engine or generator!

[GordMay]

IMO:
While pressing the push button, the on-board DC electrical system will be connected to the hull.
If both LEDs are on, the hull is isolated.
If only one of the LEDs is on, the lighted LED indicate the isolated leg [Pos or Neg in your case], and the un-lit LED indicates the leg [Pos in your case] which is connected to the hull.
So, Neg light 'on', indicates Positive leg grounded to hull.