Wema tank level sender

[Screen Saver]

Those of you whom have the Wema ( and copies of) Tank senders, be they fuel, water or grey water Im sure must have experienced the sender showing empty when it's not and no Im not talking about those with bad or broken connections. From there you probably replaced the sendor at aroun $50-$80usd
If you have ever investigated this, you will most likely find that the black float which is also a magnet has lost its magnetism.
You can prove this by simply grabbing any magnet and slide it up and down the stainless tube when you have it out and still connected. You should see the guage display works just fine.

So I have drilled these magnetic floats a couple of times and inserted a magnet, then epoxy it in and it all works. This is a bit tricky finding a magnet enough to trigger the read switches in the tube, fitting it back through the whole and still floating.

So I'm wondering if some enterprising individual has had the black magnet thing that slides up and down the tube remanufactured in two halves. All you would need to do then is break the old one off (or not) and clip the two halves of the new one together. Should not be worth more than $10

So anyone "Been there and done it " as they say ?

 

[ggrizzard]

Oooh, good question. Hope someone has.

 

[JoeWhite]

Good detective work, Screen Saver. I use this sender on my diesel fuel tank. No problem yet after 10 years. I hope someone has a solution.

 

[jssailem]

I installed one of these sensors in my diesel tank.

If I was going to cut the donut off I would try using a Dremel tool with a cutting wheel.

On the other hand, I wonder how strong the magnets need to be to trigger the internal switches. Perhaps imbedding a small magnet is all it would take. That is if the magnet is the issue. It may be the failure is the reed switches in the column.

 

[JamesG161]

So I'm wondering if some enterprising individual has had the black magnet thing that slides up and down the tube remanufactured in two halves.

Why?

When I talked with Wema, the new Slider is designed not leak or absorb the fluid.

Cheap part = $90

Jim...

PS: I would rather be Sailing

 

[Screen Saver]

Yea the slider isnt leaking or absorbing fluid, its simply losing its magnetism.
I can slide a magnet up and down the tube and it all works just fine.
Yea your right $90 is not that expensive as a 1 off, when you multiple that by 5 or 6 ie for every tank that $500-$600 is prompting me to look why there is not a bub $20 fix. (which i may !!! now have)
I fixed one before by embedding (drill and epoxy) a small magnet, but it was hard to find the right one, light enough for the float to still work and strong enough to trigger the read switches. One of the magnet companies here directed me to Extra Strong Neodymium magnets which I bought yesterday. They are strong and light weight, so I'm hopeful they will work. I will test it out on the one float that Have nearly destroyed with all my prior attempts.

 

[Screen Saver]

Ah fixed for $7.00 AUD. So I have played with one i wrecked a year or so ago, hence why its not nice and neat. The magnets you see cost $7.00 aud and size is shown on the packet. Once I had the old sender in my hand I filed a bucket with salt water not thinking at the time that salt water has more flotation, and when I woke up I refiled the bucket with freshwater and simply sat the magnet on top to check it was going float ok, which it did. I then removed the old magnet (breaking a bit more of the float ) epoxied the new one and tested by hand on the floor. Put it all back and all good.
So I will wait a few days, then try one of the others, this time neatly drilling a whole, pushing the magent in and I expect that will work. If I put some epoxy in the whole first then push the magnet in, and some more epoxy on the outside Im thnking it will stop the magnet from rusting. Yep if was not retired and was still Project director in IT for sure it would have been cheaper to by 5 new senders, but these days my time is not worth $1500 pd, so I can now buy a good bottle of scotch

 

[Mark Maulden]

As a retired electromagnetics engineer, permanent magnets just do not “lose“ their “magnetism”. Especially in the timeframe of our sailing ”careers”. My question would be is the wiring to the indicator routed along with other dc current carrying devices.

 

[Screen Saver]

I confess to knowing little about permanent magnets. But I can tell you any DC interference would upset this circuit and there is nothing near by known to me. Further its not just one tank. Screensaver is well used (10k nm/pa) more than 90% of cruisers I come across in my last 15 years, this often makes me at the forefront of such things. My reasoning for the problem was that the actual float(s) have worn on the inside where it slides up and down the pole. There is quite a bit of play in these, more movement than on a new one for example, and no the gap is not the issue. I bought one as a spare. I dont know how they magnetize this device, its not like there is a magnet inside it. So rightly or wrongly so I assumed that it was some sort of coating that with all the movement had worn off, or my alternative theory was the constant slopping perhaps banging had caused the loss. I might be completely off track here, but it was all I could come up with. If you think my reasoning is not sound please say so, because that suggest it will fail again and I dont want to touch the others if Im wrong.

 

[Hello Below]

So I'm wondering if some enterprising individual has had the black magnet thing that slides up and down the tube

Maybe cut the stopper end off the tube, slide the old magnet off, slide the new magnet on and construct a new stopper with epoxy (aluminum screw???). It is unlikely that Wema manufactures the magnet themselves so it is a matter of finding a source that does. Maybe here is a start:
Digikey - Australia - Sensor, Transducer Accesories
Good luck.