freshwater tank sensors

[panman52]

I have a Tribute T620 motorhome the water level indicator on the control panel is erratic and just keeps recycling all the time when the button is pushed, in the manual it says to remove both the leisure and running battery fuses from the charging unit (9 and 10) leave for 30 seconds then switch back on this will reset the software in the charger, having rebooted it works as normal for about 5 minutes then goes back to its present state. I have contacted sargent they say it could more than likely be a sensor problem and to check this out first ,has anyone first hand experience, I have looked at the water tank and cant see any of the sensors is there a cover over the tank and what kind of job is it, appreciate any help, many thanks.

[Billggski]

The classic remedy is to fill the water tank with soapy water and go for a run around a twisty course to slosh it around. Worked for me.

[panman52]

I've never heard of that one, I put dishwasher tablets in the waste water tank and that works fine

[Derek Uzzell]

Welcome to the Out&AboutLive forums, Roger.

 

There are several types of contents-level measuring arrangements for motorhome freshwater tanks, but (probably) the most common for UK-built vehicles involves a set of ‘probes’ inserted through the tank’s upper surface. (Examples on following link).

 

https://www.leisureshopdirect.com/water/caravan-plumbing/water-supply-fittings/fresh-and-waste-water-level-indicator-kits

 

The probes can develop a film (especially when hard water is regularly used) causing inaccurate readouts and cleaning the probes may fix this. This earlier discussion refers

 

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Fresh-Water-Level-Sensor-faulty/30423/

 

(Normally, with a probe system, readouts may be inaccurate but the ‘cycling' you’ve described is odd. If your Tribute has a probe-type system I suggest you confirm that the electrical cable attached to the top of the probe-unit is properly connected and see if cleaning the probes does any good.

[panman52]

Hi Derek, thanks for that information the link above was useful I think first stop will be to try the freshwater tank cleaner, must be worth a try.

[Keithl]

Hi Roger(?),

 

As you have mentioned Sargent I would guess your fresh water sender is the same as an AT so if you look at the wiring diagram here... Link and specifically page 5 you will see that the sender will have 5 wires, the W/O (White/Orange) being ground and the other 4 being signal wires from the Sargent ECx PSU.

As you say that there is a reading for a few minutes then it all fails I would hazard a guess that you have a wiring fault. My suggestion would be to unplug the sensor wires from the PSU and do a conductivity test for each wire down to the sender. I suspect one or more wires are either damaged or shorted to ground.

 

HTH,

Keith.

[Derek Uzzell]

This 2010 MHFacts thread discusses Auto-Trail fresh- and waste-water sensors

 

http://forums.motorhomefacts.com/53-autotrail-motorhomes/64648-water-tank-sensor.html

 

It might be useful to know when Roger’s Tribute T620 was built just in case the problem has reared its head on similar-model/similar-age motorhomes. (Unlikely, but one never knows!)

 

I’m doubtful that sensor cleaning is going to fix this particular problem, but if cleaning is to be tried it would be better to clean the sensors directly rather than rely on a cleaning fluid put in the tank. But how practicable direct-cleaning the sensors will be will depend on the type of sensors the Tribute has and how easy it is to reach them.

 

I agree with Keith that this ‘cycling’ thing sounds much more like a wiring fault than caused by dirty sensors.

 

 

[Billggski]

It was the dealer who suggested the cleaning method, probably because it was under warranty and it saved him having to do anything himself. As I said it worked, but it was the grey water tank as I remember now, which is harder to get at than the freshwater which is under a seat.

[panman52]

All this is very helpful thank you, my Tribute has just had its first MOT 62 plate so its just 3 years old and looking around the motorhome show this year it seem to be fitted with the same as AT, the EC155 power supply unit and the EC51 control panel. having had a quick look underneath I cant make out weather the talk bolts straight on to the chassis or has a cover over it.

[Derek Uzzell]

This MHFacts forum-thread relates to a 2010 Auto-Trail Apache’s water-level sensors

 

http://forums.motorhomefacts.com/53-autotrail-motorhomes/121227-fixed-autotrail-apache-water-level-sensors.html

 

and it may help regarding the type of sensor-system used by Auto-Trail and how to access the sensors and the wiring. (I hadn’t realised your motorhome’s fresh-water tank was external.)

 

If your Tribute has a similar arrangement, getting at the sensors (never mind physically cleaning them) would be a bit of a pain, so I suggest you first do as ‘downerhouse’ did with the Apache and check that the electrical block-connector for the sensors on the Sargent control-panel isn’t loose.

[audiseller]

I don't think many if any of these systems read accurately so wouldn't take much notice of any readings personally. Fill it at every opportunity and if it shows half full take it with a pinch of salt.

[Derek Uzzell]

A GOOGLE-search on “motorhome water tank level indicator” confirms that problems with contents-measuring systems are far from rare

 

https://www.google.co.uk/?gws_rd=ssl#q=motorhome+water+tank+level+indicator

 

but most systems should be capable of providing readouts sufficiently accurate to be useful.

 

My current Rapido (and my previous Hobby motorhome) has a CBE-branded probe-type system to indicate how much fresh water there is in the tank. It’s inevitable that the readouts will be affected by the ’stance’ of the vehicle (ie. whether it is parked nose-up, nose-down or leaning to the side) but levelling the Rapido (and Hobby) allows the system to provide reliable and repeatable information.

 

With a probe-type system it’s essential that the probe lengths match the depth of the water tank. If the probes are too short the gauge's readout will only be accurate when the tank is full. From that point onwards - as the tank empties - the gauge will under-read. But whatever system is employed it would be sensible for users to familiarise themselves with their system’s limitations and how the gauge’s readouts should be interpreted.

 

The latter should be relatively easy to do if the water tank is accessible and translucent allowing the water-level to be seen. Just fill the tank and check how the gauge readouts alter when water is drained from the tank. If a tank’s contents-level cannot be ascertained visually, a tank’s capacity will be usually be known. In this case, fill the tank and drain out the water using a known-capacity container (eg. a two-gallon bucket) noting what happens on the gauge. For example, if a tank’s capacity were 16 gallons, draining 2, 4 and 6 two-gallon bucketfuls of water from a full tank should produce readouts of, respectively, 75%, 50% and 25% full.

 

On-line comments about motorhome fresh/waste water gauges often mention inaccuracy, but that’s not usually the big problem as motorcaravanners will become familiar with their water usage and most people seem able to appreciate that contents-level readouts won’t necessarily be linear. Advice is generally sought when there’s plainly something badly wrong, when a gauge does nothing, or shows full when a tank clearly is not, or (as here) is erratic.