Diagnosis problem

Hi all, can I ask for ideas to help me diagnose an issue with my freshwater tank levels?
He vehicle is a 2016 Broadway ek....with I believe a Sargent control panel.

Ver been chatting to Daniel at motorplus Derby who is in my humble opinion very knowledgeable, however he appears to be confused by the symptoms and I'm trying to assist by asking here for possible solutions.

The filling proceadure works correctly I.e. The control panel shows incremental filling from zero to 100%.
However after the tank is full, the levels start to drop without drawing water from it?

No leaks are evident, indeed...the tank has proven to remain full.....the tank levels will eventually drop to zero and the alarm will sound indicating that the water has run out...( though last w/e) the alarm did not sound?
The level also went back to 25% after reaching zero...

Has anyone seen this behaviour before? And perhaps help to tie the cause down to a limited number?

Ray.   

There are two possibilities and we have just gone through both
1. Sensors in tanks ( new ones under warranty didn't cure )
2. Suggested on here reset the panel did work (via set up) rather than a straight forward off and on reset. ( up and down arrows will put you in set up then scroll through

Same procedure sorted an iffy step out

Thanks Roger, I did wonder if a reset might work, I'll give Dan a ring on Monday and see if he can guide me through that procedure.

Ray

I've had this problem with older model vans , I switch off the control panel as Roger has mentioned and reset this usually does the trick .
Boaby