water tank depth guage - fixed that too!

One of the apparently common failings of the westfalia kit is the depth guage inside the onboard water tank. I made it a mission to replace mine until I found that they could be repaired. Here's what I did

A post from Lagerhead on 80-90 was really helpful as it led me to understand how these work and consequently how the inners must be constructed to enable it to be manufactured consistently.

As he says, they work by the float (which contains a magnet) opening and closing 2 reed switches to effect a pre-determined amount of resistance (through the two inline resistors). The amount of resistance makes 1 of the 3 LED's in the control panel light up. Simply really!

It appears to me that these sender units quite commonly fail for 2 main reasons:

a. the plastic rod leaks and takes on water which causes corrosion and deformation of the copper strip.

b. the magnetic reed switches break (probably because the rods get bent or they are made to bend due to water getting in and so causing the double sided copper clad "rod" to bend)

NOTE- these rods are actually VERY fragile, so NEVER try to straighten a bent one - this is what breaks the glass reed switches!

So, to repair them (mine was pretty well trashed, so i reckon that they can always be fixed as long as all the main component parts are still present):

1. unplug the 2 wires to the depth rod (black and green) from the clear multi-plug connector block which is found in the rearmost locker under the westy table (you will need to remove one small screw to swing a metal plate back to reveal the lid to the water tank).
   
   
2. Remove tank cap/lid and carefully withdraw complete with rod.
   
   
3. You may have to carefully "break" the glued connection of the rod and the grey mounting cap, mine slipped out easily but they were originally glued.
   
   
4. Snip the connections of the two wires where they enter the top of the plastic rod to free it.
   
   
5. using a sharp knife, break the seal of the glued grey plastic cap at the bottom of the rod and remove the plug (this is where they seem to leak from)
   
   
6. push the inner rod through from the top (where the wires were) or use thin-nosed pliers to pull it from the bottom - it should only be glued / sealed slightly at the top if at all.
   
   
7. Once you have all the pieces, it should be obvious that the tiny magnetic reed switches are broken, mine were filled with water and like tiny spirit levels with bubbles in too!
   
   (all the bits..)
   
   (upper switch..)
   
   (lower switch..)
   
   
   
8. Obtain new reed switches and desolder the old ones to replace with the new, ensuring the rod itself is kept absolutely flat and straight - DONT TRY TO BEND IT AFTER SOLDERING! or you will break the reed switches again!
   (The switches can be found at Maplin, RS and Farnell, but look carefully at the description, these are miniature switches and there's no room for anything bigger! The top one is a SPST type - single pole, normally open (ie open circuit until a magnet goes over it), the lower one I found much more tricky to locate a supplier for as it's a DPST - double pole - this one has to be soldered in to be closed and the "open" leg cut off short and not touching or soldered to anything.) You can easily test the switches with a multimeter and a magnet to check connections etc.
   
   
9. Ensure there are no short circuits, solder lumps or bumps, or anything more than about 2-3mm above the surface of the rod, as if there is, it may not work, or may not go back into the sleeve.
   
   
10. Depending on how easily your rod will feed back into the plastic sleeve, you may need to go from the top or bottom - if you cleaned all the glue out, it should make no difference. However, if you have to push it up from the bottom, then carefully push the copper rod complete back up into the plastic tube, pushing it through about 1/2" clear so you can resolder the wires to both sides at the top.
    
    OR.. solder the wires on first (doesnt matter which goes to which side, but make sure no solder short circuits the two sides!) and push the rod back into the tube from the top.
    
    
11. push the copper rod back in flush, seal with silicon or similar to prevent moisture getting in, replace the bottom plug and glue it / seal it.
    
    
12. I used bathroom sealant to seal the lower plug and also the seal between the rod and the grey plastic top that is screwed to the tank cap- whatever you use, remember that's your drinking water in there!
    

Hey presto - you should have working LEDs again; stand back an admire - oooooooooh, fairy lights! (the top switch on the display should show you battery and water levels)

If you need the reed switches and cant get any, I have some (only a few of the double pole ones tho) and can supply one for each of the top and bottom for £10 inc postage. I might even consider repairing these for others, it takes about an hour once you've got all the bits, or 3 weeks if you learned on the way and had to track down the parts like i did!

Hope this helps!

kitchen / bathroom silicone sealant should be ok. As far as i know, that's inert.

i have fixed mine but still no magnet

can you show a larger pic of the floating magnet or describe what it is made of please Calvin?

mine is broken too but the repair seems a bit technical for me- no soldering experience since burning my fingers at school-  any chance you would consider repairing it and how much would you charge for this service.

thanks pete