Westy water tank level sensor repair

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

There have been more than 2000 views of this topic in the
‘Westy Useful Threads’, it is obviously a common problem. As there are only
7000 odd views on the Roll Call it looks like at least 1 in 4 have this
problem.

When I bought my van the sensor didn’t work. I repaired it
by replacing the reed switches and resistors, resealed it and it worked all
over the Autumn and Winter and failed on my summer holidays!

Full of moisture and rust. I repaired it again, this time
like holydiver, I replaced the tube as well as the switches. Once again it
worked all over the Autumn and Winter and failed on my summer holidays! This
time I took it out as soon as it failed. It was full of water and I realised
what is the cause of this problem.

Untypically for Westfalia, I believe it is down to a design
fault. When the tank is filled to everflowing, the overflow is 10cm or so above the top of the tank leaving a head of water to slightly pressurise the tank. The sensor is secured to the tank lid by three screws through a plastic
flange with a fibre gasket in between. I was amazed to discover that the tank lid
had warped leaving a gap of almost a millimetre between the mounting holes.

 No
way would a thin fibre gasket fill this gap. Furthermore, the flange face has
the maker’s name moulded onto it so there is even less sealing area.

During the winter, most of the time my water tank is empty, come my holidays,
the tank is full to the brim. There is water splash or condensation, and
temperature changes draw water through the gap between the flange and the
warped cap where it runs down into the sensor tube. Sensor fails!

My solution is to follow holydiver’s excellent tutorial BUT, when drilling out the hole in the
flange to 10mm, drill right through.
When you insert the tube do not leave it flush with the flange but push through a further 10mm or so. 

Open
up the hole in the lid to 10 mm. Whilst you are at it open up the mounting
holes to M4 so you can put some decent size screws in there. Now, when you
assemble it to the lid, the end of the tube goes through the lid into fresh air
and cannot get water drawn in. Whilst I was at it I also used a 8mm ‘top hat’
grommet to try to improve the cable entry to the sensor.

Finished top view.

So thats it, just need some nice weather to get away and fully test it.

(By the way you can get 10mm PVC tube from B&Q)

Edited by Pete Westy - 22 Aug 11 at 11:21