Water Tank sensor LM30

[mastetop]

The water tank sensor on my LM 30 has stopped working ! Can any one share info as to where the sender is located and can it be replaced with a new one or where should i be able to purchase a replacement.

Thanks.

[Brian & Glenda]

On my LM32, the water tank is located beneath the galley cabinets. In the bottom of the cupboard under the sink, is an ~8" x 10" wooden panel resting on a recessed lip of the fiberglass floor of that cupboard. Lift that wooden panel, and the water tank lid is below. Undo the two nuts that hold down a metal bar over the tank lid, and the lid will lift out with the sending unit attached. The sending unit is a VDO float style sending unit. Make sure you get the one for fresh water though, as I understand it is made from different materials that the one for a fuel tank.

I believe that this is the unit: www.summitracing.com/parts/vdo-226007.

I replaced mine a few years ago with one I bought from the USA (not this firm, but I'm sure there are more suppliers of VDO components in Europe than there are in Canada and USA combined.) My exact product info is on the boat and I'm not there at the moment, but I'll try to remember to look it up and get back to you.

Hope that helps,
Cheers, Brian.

[Brian & Glenda]

I forgot to say that if you go to another brand of sending unit, to be sure to match the electrical capacity of the sending unit, to that of the gauge. There seems to be at least two different ohm range ratings for various units.

Or... you could perhaps replace the float switch and the gauge if necessary with a more modern level sensing unit such as: www.scadtech.com/tank_monitors, or another such unit. Some folks claim trouble with float switches but I think they are fine for clear liquids such as fuel and water tanks ... but not for black water tanks.

Brian.

[Sula]

Jun 30, 2020 18:03:27 GMT Brian & Glenda said:

I forgot to say that if you go to another brand of sending unit, to be sure to match the electrical capacity of the sending unit, to that of the gauge. There seems to be at least two different ohm range ratings for various units. 

I believe that there are just two basic types.  Some have resistance (ohms) starting at zero when empty and increasing as it fills, and the others have high resistance when empty, decreasing to zero when full.  I seem to recall that ones made in (or for) the USA market tend to go one way, and the European ones the other way, though I can't remember which is which. 

(Not directly relevant to the OP's query, but my LM27 (water tank port side behind and below wheelhouse), is monitored by a simple sight tube (clear tube connected either end to top and bottom of tank, so you can see what level it is inside).  You have to lift the cockpit floor/engine cover cover to see the level, so not ideal, but perfectly practicable.)  

[Brian & Glenda]

I found the box my replacement float style, VDO brand, fresh water tank level monitoring gauge sending unit came in.


It bears the markings:
226-452
Water Level Sender
V1555001021D
Made in Switzerland

The Bar Code bears the numbers 7 54059 01024 3

Our boat is an LM32 with a 55 Gallon fresh water tank, while the original brochure (See John C's post "LM30/32 20 Page Brochure" in the "What are Wheelhouse Yachts Like" folder) shows the LM30 was built with a 44 Gallon tank, but I suspect that the gauge would be the same for both tank sizes as the position of the float switch on the vertical shaft is adjustable.

Hope that helps,
Brian.