Water gauge showing 100% at all times

Why is this happening, anybody got an ansewer ?
At first the water gauge on our 2019 Bourton intermittently when we travelled with the tank half full would show 100% on arrival, the following day it would show the true level. We decided to then travel with it empty to see what would happen, if the roads where dry it would read true, if the roads where wet it would show 100% and then show true the next day.NOW IT SHOWS 100% at all times, wet or dry. its now a problem as we can't get the whale pump to pump from the barrel because of no foltage at the connections due to the gauge showing 100%. Has anybody any idea whats going on and how to fix it. Thank you in advance.

If no power to the fill point, assuming external pump is switched on, must be the float cutoff is stuck at the top full position? Why it should show full, don't know.

Have you got sensors like this in the side of your tank as they do play up and require cleaning

There seem to be two separate and unrelated issues here.  First, power not getting to the Whale inlet socket which could be caused by several things, one of which could be a stuck float valve as suggested by Peter L.  Second, spurious readings being shown on the tank gauge which is quite common - I have it all the time.  As Glyne has said this can be rectified by cleaning the sensors in the tank.  This can be done by filling the tank with a descaling/cleaning solution which is covered in other threads.  I don't think the state of the road will have anything to do with it although I suppose salty spray off the road could be affecting some of the electrical connections under the van.

I seem to recall a similar forum post where it was found that the external connections to the tank sensors had suffered water ingress causing spurious readings.

Sensors do play up but if they need cleaning then readings are low, not high. Your 100% readings are most likely the result of damp and general road filth on the outside of the tank which may be .are worse if there is gaffer tape applied over the connection tin a useless attempt to keep them dry (put on in production on my van!). Clean the tank around the sensors and put a separate blob of silicone sealant over each one. Mark told me to do that and I haven't had false high readings since. (The Sargent measures the resistance between each of the top 4 sensors and the bottom one - no connection means out of the water but water inside or damp crud outside will fool the Sargent).
The Whale will only let water in if the solenoid valve below it has power. That is powered from Habitation electrics which must be on via a level control on the tank. On my van that is a simple float switch, entirely separate from the sensors. When the tank is full that float switch powers a relay under the wardrobe which lets power to the solenoid valve. If tank is full and I rock the van I can hear the relay clicking. If the float switch is stuck up (unlikely) or there is a bad connection or a faulty relay the result is that the solenoid valve will not open.
There may be a link between your two problems I recall that a couple of months ago someone on here or on the Facebook forum insisted that on their van the top 100% sensor had a dual function - both 100% level indication AND cut-off sensor. I may have been wrong to not believe them. I believe they had the EC700 system. The service dept at AS will tell you what your van has for the full cut off if you quote your build number.
I hope all that might be some help to you

Thanks Ron.  I might now have a look at the external sensor connections on both my tanks.  I have the EC700 and have not had the OP's problem with power not getting to the outlet socket other than when the EC700 CP autofill button is not switched on and lit or when the tank is full.  I have always assumed that power is cut off when the tank is full by a separate float switch at the top of the tank rather than the full sensor which can be wrong.

Hi all. I now have the same problem with the clean water tank showing 100% and not being able to fill with the aqua roll, which is a real nuisance.
Couple of questions  please

Which face of the tank are the sensors positioned on a Bourton 2020 model? Offside or nearside. Front or back

What do you clean the sensors with? Steel brush,  stiff  brush or just soap water and a rag? 

Also, is there an access point to the tank, where you can put you hand in and clean the inside? I have seen this on some motorhomes.

Finally, for descaling ect, any recommendations for a cleaning product that I can pour into the tank?

Thanks in advance

Widget wrote:Hi all. I now have the same problem with the clean water tank showing 100% and not being able to fill with the aqua roll, which is a real nuisance.
Couple of questions  please

Which face of the tank are the sensors positioned on a Bourton 2020 model? Offside or nearside. Front or back

What do you clean the sensors with? Steel brush,  stiff  brush or just soap water and a rag? 

Also, is there an access point to the tank, where you can put you hand in and clean the inside? I have seen this on some motorhomes.

Finally, for descaling ect, any recommendations for a cleaning product that I can pour into the tank?

Thanks in advance

On my Nuevo there is no access to the inside of the tank.  It may be possible to unscrew each sensor for cleaning but I haven't done that.  I have only used citric acid solution to descale/disinfect the inside of the tank which includes the sensors.  My freshwater tank sensors are difficult to access and are on the front face of the tank.  I'm waiting for dry weather to apply silicon sealant to the outside of each sensor including on the waste tank sensors which are easier to get at.

Widget wrote:Hi all. I now have the same problem with the clean water tank showing 100% and not being able to fill with the aqua roll, which is a real nuisance.
Couple of questions  please

Which face of the tank are the sensors positioned on a Bourton 2020 model? Offside or nearside. Front or back

What do you clean the sensors with? Steel brush,  stiff  brush or just soap water and a rag? 

Also, is there an access point to the tank, where you can put you hand in and clean the inside? I have seen this on some motorhomes.

Finally, for descaling ect, any recommendations for a cleaning product that I can pour into the tank?

Thanks in advance

Unless they have changed the design (which I doubt), the Bourton fresh water tank is split in two, the top being under the offside bench seat and the bottom under the floor. They are connected together with small bore tubing. There is access in the top of the tank under the seat including to two of the five sensors.

The way the sensors work is with respect to the bottom sensor, if its connected to one other (any one) the gauge will show 25%, to two = 50%, to three = 75% and to the four = 100%. A permanent 100% reading shows that the four top sensors are all connected to the bottom one - they do not need cleaning. This will happen when the tank is full but also if the multiway connecter in the wiring loom under the floor gets wet.

I use Kilrock Descalene for descaling, it is safe and effective.