Fresh Water Tank Level Gauge Trouble

[Tallpaul]

Hi been experiencing problems with my Fresh Water level sensor gauge. I own a 1997 Fiat Ducato AutoRoller. All started when I had to redo all the wiring as it was in such a mess and very dangerous. Everything else is all sorted and works as it should, apart from my the level gauge on my fresh water tank.

I'm a bit confused to how it works with regards to needing power. As there is only 1 black cable (sleeve with 4 different coloured wires within it. This runs from the control panel to the tank via a connector mid way (connector is just a 4 way male and female multi plug connector. I have connected it up as it was but it doesn't work, always shows empty even when full or three quarters full. And just recently some strange red light came on, on my control panel where the water level gauge is. Not sure what it is, looks like grey waste water tank by the picture.

If anyone has experience of fitting and installing water tank sensors, level gauges etc. Any advice or pointers would be very welcome.

Regards
Paul

 

[torwood]

Not certain but I assume one lead is a low voltage supply and the other three relate to each third of the tank water level. If it is like my tank the sensors are stainless steel rods and the on-board electronics reads the capacitive value between each rod where there is water and this gives the level in the tank.
These rods become oxidised over time and give false or zero readings and need cleaning. Can you remove the sensor from the tank and clean it, also if you have been moving the connections about have you connected them wrong hence the red light warning?

As for voltage and power requirements check with a voltmeter between each contact on the PCB at the panel end for a voltage, may be 12 or 5 volts (most likely) Once you identify the feed it should be possible to work out 1/3, 2/3, and 3/3 - but if you can get the sensor out of the tank these should also correspond directly to the water level in the tank.

 

[harrow]

Yes I guess there is a op-amp in the electronics

:idea-007::idea-007::idea-007:

 

[Tallpaul]

Very good advice and comments

Not certain but I assume one lead is a low voltage supply and the other three relate to each third of the tank water level. If it is like my tank the sensors are stainless steel rods and the on-board electronics reads the capacitive value between each rod where there is water and this gives the level in the tank.
These rods become oxidised over time and give false or zero readings and need cleaning. Can you remove the sensor from the tank and clean it, also if you have been moving the connections about have you connected them wrong hence the red light warning?

As for voltage and power requirements check with a voltmeter between each contact on the PCB at the panel end for a voltage, may be 12 or 5 volts (most likely) Once you identify the feed it should be possible to work out 1/3, 2/3, and 3/3 - but if you can get the sensor out of the tank these should also correspond directly to the water level in the tank.

Hi thank you for you lengthy explanation and advice on my problem, yes that all makes sense to me. This site is proving to be much better than the Motorhome Matters forum on the Out and About Site as posted the exact same question on there forum a few days ago, been viewed over 60 times but no replies or comments. Put it on here and within 12 hrs of posting received 2 replies.

Good Work Wildcamping

 

[Tallpaul]

Thanks for the reply

Not certain but I assume one lead is a low voltage supply and the other three relate to each third of the tank water level. If it is like my tank the sensors are stainless steel rods and the on-board electronics reads the capacitive value between each rod where there is water and this gives the level in the tank.
These rods become oxidised over time and give false or zero readings and need cleaning. Can you remove the sensor from the tank and clean it, also if you have been moving the connections about have you connected them wrong hence the red light warning?

As for voltage and power requirements check with a voltmeter between each contact on the PCB at the panel end for a voltage, may be 12 or 5 volts (most likely) Once you identify the feed it should be possible to work out 1/3, 2/3, and 3/3 - but if you can get the sensor out of the tank these should also correspond directly to the water level in the tank.

Mine as 4 stainless steel rods, 2 are clean one is scaled up. Took water sensor out, cleaned and descaled all 4 probes. But looking at my system, it appears that mine as a reserve probe as well as my gauge display shows R, 2/3, 2/3, 3/3. As there is a separate 12v positive and negative cable which feeds the control panel. I'm wondering if then this provides the voltage to the probes. And that's why there are only 4 wires fed from from the water level gauge display on the control panel to the fresh water tank.

Going to fit it back on today and check all connections etc.

 

[Tallpaul]

Quick Update

Hi everyone, thanks for your replies, well, removed the stainless steel rods and sprayed them with limerite descaler left to soak over night, then just wiped the limescale build up off. Refitted and added an earth to one of the 4 wires, and hey presto. All working perfectly fine again now and pretty accurate too.

Just the problem of the red light on water gauge on the control panel constantly on even when everything is switched off. Bit weird and I have no idea what is is for.

So if any one can help I would be extremely grateful. you can see it in my first entry, one of the 3 photo's

Regards
Paul

 

[shortcircuit]

Delighted you got your problem resolved. I had a similar problem which I never resolved as I subsequently sold motorhome, however having contacted Sargent whose panel it was it did not matter which way the wires, other than the earth, were connected as it was a digital and not analogue.

 

[scotsjon]

Surely the red light is telling you that it thinks your grey water tank is full? Likely similar problem. The probes are probably covered in crud making the gauge think there is water in the tank.

Agree with you comments that Italian wiring is diabolical.

 

[Fazerloz]

I wold have thought the grey water tank will have a float switch [less likely to be bothered by crud in dirty water] and not probes. I would think the float stuck showing full tank. Mine had come loose and was half hanging out of the tank putting the full tank alarm on.

 

[jagmanx]

Agreed

Surely the red light is telling you that it thinks your grey water tank is full? Likely similar problem. The probes are probably covered in crud making the gauge think there is water in the tank.

Agree with you comments that Italian wiring is diabolical.

Our "grey water full" Alarm often displays red after rain...
Surely this is not a problem.
Fresh water 90 litres used for drinking and cooking and toilet so maybe only 80% goes to grey water.
Thus even without a gauge you can estimate when getting full.
We can easily go 3 days without topping up fresh water.
So only need to empty grey water every 3 days.
There are many places to dispose of grey water.
Both properly and discretely.
We do this usually every 2 days but daily if the opportunity arises.

 

[scotsjon]

I wold have thought the grey water tank will have a float switch [less likely to be bothered by crud in dirty water] and not probes. I would think the float stuck showing full tank. Mine had come loose and was half hanging out of the tank putting the full tank alarm on.

Dunno what is more common. Our Rollerteam autoroller has the same four probe setup in the grey water as it does in the fresh and shows the same thirds scale. This all handled by the Nordelettronica panel. If we get sink crud caught on the probes it can eroniously show full.

If in the process of replacing amd improving much of the factory wiring, but the nordelettronica panel will probably stay due to the problem of accessing all the wiring. The crappy nordelettronica charger has gone though.

 

[Tallpaul]

Thanks for the reply

I wold have thought the grey water tank will have a float switch [less likely to be bothered by crud in dirty water] and not probes. I would think the float stuck showing full tank. Mine had come loose and was half hanging out of the tank putting the full tank alarm on.

I wold have thought the grey water tank will have a float switch [less likely to be bothered by crud in dirty water] and not probes. I would think the float stuck showing full tank. Mine had come loose and was half hanging out of the tank putting the full tank alarm on.

Hi there
Just figured out whats the problem with my water gauge showing red light all the time. When re-doing all the wiring in my camper, there was a twin core cable (Standard Blue & Brown) going to waste (grey water) tank. Attached by a choc blok to 2 stainless steel probes that were corroded. So I removed it thinking it was maybe a waste tank heater to prevent freezing.

wiring looked dodgy as was piggy backed onto other wiring....

But makes sense now this was the wiring for the waste tank level. Just confused how it should be wired as when you look at the new freshwater and waste water tank sensors. They have 4 wires for fresh water tank and 2 wires for waste tank.

Mine only has a 4 pin connector plug on the rear of the water gauge on the control panel, Blue, White, Brown and Black. These all go to the 4 stainless steel probes on the freshwater tank. There are no extra wires to connect to for waste tank. Maybe that's why they were piggy backed to these wires.