Black waste tank sensor..

[robtheplod]

Sorry for the second post today, just gauging opinions on things before I start. As this is the gauge for the pumpout tank I want to be 150% sure of everything before I do anything!

 

In a nutshell the gauge for the waste tank doesn't work - its an after market Wema, which is good as items still available. The sender should go from 240 to 30 ohms, but always reads 240, so empty.. not very helpful. The dial reader is fine as if I short the wires to the sensor it reads full.

 

New ones are available : https://wema.co.uk/collections/marine/products/holding-tank-sender?variant=29347886087 and it also says you can clean them - not sure I really fancy that??   The tank is 60cm deep so assume I'd need the 51cm sensor?

 

anyway, has anyone had experience of changing these, assume its screws out, break seal, gag a bit, then put new one in, seal and screw up. What type of sealant is recommended - looks like a black seal on it currently?

 

Any points/hints/tips appreciated.... yes we will be changing to cassette/compost in the future but until then......

 

[WotEver]

Why buy a new one if the old one simply requires a clean?  Not moving from the ‘empty’ reading suggests to me that it’s little more than a stuck float. Undo those screws, lift it out, give it a good clean.  If it’s more than a bit of stickiness then at least you’ll now know which sender you need to buy to replace it. 

[robtheplod]

Just now, WotEver said:

Why buy a new one if the old one simply requires a clean?  Not moving from the ‘empty’ reading suggests to me that it’s little more than a stuck float. Undo those screws, lift it out, give it a good clean.  If it’s more than a bit of stickiness then at least you’ll now know which sender you need to buy to replace it. 

I was afraid someone might say this - sounds like an awful job but yes, it makes sense.. maybe do it when nobody else is on the boat and its a day I can open all the windows!!  thanks for the reply..

[cuthound]

I fitted an MSC gauge to my boats waste tank.

 

Easy to fit, affordable and reliable.

 

http://mcsboatproducts.co.uk/

[blackrose]

16 minutes ago, robtheplod said:

What type of sealant is recommended - looks like a black seal on it currently?

 

 

I use this stuff for everything. Give both surfaces a wipe with a bit of white spirit to clean them first.

 

https://www.toolstation.com/stixall-adhesive-sealant-290ml/p60981?store=N3&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gclid=Cj0KCQjwt5zsBRD8ARIsAJfI4Bi51YisOApdh2Z2mc65AADUHdBJgslk8PwhuvApyyF8D8gfWQoteRsaAjqfEALw_wcB

 

[WotEver]

9 minutes ago, robtheplod said:

I was afraid someone might say this - sounds like an awful job but yes, it makes sense.. maybe do it when nobody else is on the boat and its a day I can open all the windows!!  thanks for the reply..

It’s just a bit of muck. Resist the temptation to lick your fingers and you’ll be fine...

[robtheplod]

Thanks to everyone's replies. I took up the challenge and cleaned the sensor - not as bad as I thought it would be. The bottom of the sensor that's submerged the most had a build up of crystals on the rod that the magnet floats up and down on, making it stick. Took 10 mins to clean and now proven all working again!

[WotEver]

Uric acid crystals probably. 

[cuthound]

3 hours ago, robtheplod said:

Thanks to everyone's replies. I took up the challenge and cleaned the sensor - not as bad as I thought it would be. The bottom of the sensor that's submerged the most had a build up of crystals on the rod that the magnet floats up and down on, making it stick. Took 10 mins to clean and now proven all working again!

 

That's why I prefer the MCS gauge, no moving parts.

 

Another advantage of a waste tank gauge is fewer pump outs. Since fitting my gauge I found the free light "tank full" indicator actually comes on when the tank is actually just over 50% full,  so it has virtually halved my pump out costs.

[Sea Dog]

16 hours ago, robtheplod said:

Thanks to everyone's replies. I took up the challenge and cleaned the sensor - not as bad as I thought it would be. The bottom of the sensor that's submerged the most had a build up of crystals on the rod that the magnet floats up and down on, making it stick. Took 10 mins to clean and now proven all working again!

Nice one Rob; you're a very brave boy! (Dont forget to wash your hands)

 

[tree monkey]

16 hours ago, WotEver said:

Uric acid crystals probably. 

In the woo and nonsense world of pee therapy, those crystals are thought to be powerful healing, unfortunately only your own so no potential selling/business opportunity

[WotEver]

3 hours ago, tree monkey said:

In the woo and nonsense world of pee therapy, those crystals are thought to be powerful healing, unfortunately only your own so no potential selling/business opportunity

They’re also what causes gout when they build up in the wrong places. 

[cuthound]

46 minutes ago, WotEver said:

They’re also what causes gout when they build up in the wrong places. 

 

Hmm, I wonder if putting allopurinol in the waste tank will stop the sensor from getting crystals on It? ???

[Chewbacka]

1 hour ago, WotEver said:

They’re also what causes gout when they build up in the wrong places. 

So the sensor has gout, must be too much red wine and cheese.........

[Sea Dog]

47 minutes ago, Chewbacka said:

So the sensor has gout, must be too much red wine and cheese.........

By jove, I think you have it! I wonder how it gets in there?