strange holding tank guage indications

[Robin]

We have a ' Tankwatch' level system on our primary holding tank which despite everything (tiddle only) discharging directly overboard via the diverter valve, occasionally shows the 'half full' light. This clears in seconds if the tank discharge pump is run. But how is the gauge seeing any level at all, how could it get there? Could the diverter be leaking minute amounts to tank that builds up over time (several weeks), or could it be air pressure perhaps though the gauge works via floats on a tube that rise and fall. I'm reluctant to remove the sender for cleaning as it is a PITA to access.

 

[Robin]

We have a ' Tankwatch' level system on our primary holding tank which despite everything (tiddle only) discharging directly overboard via the diverter valve, occasionally shows the 'half full' light. This clears in seconds if the tank discharge pump is run. But how is the gauge seeing any level at all, how could it get there? Could the diverter be leaking minute amounts to tank that builds up over time (several weeks), or could it be air pressure perhaps though the gauge works via floats on a tube that rise and fall. I'm reluctant to remove the sender for cleaning as it is a PITA to access.

Bump. I guess this has everyone else baffled. too...

 

[Forty_Two]

I have a Tankwatch. Mine has 3 floats which are user adjustable for height. I set the lowest so it changes from green to yellow led with very little in the tank to make it easy to know when its empty.

The second float changes from yellow to amber leds & is set at 3/4 with the third float just below full & changes to red led & disables the electric toilet pump.

Hope that explains it a bit assuming we have the same model. I clean the sender once per season normally.

 

[KevinV]

Silly question, but does it go to "full" if you don't pump it out? That would help with your diagnosis

 

[Robin]

Silly question, but does it go to "full" if you don't pump it out? That would help with your diagnosis

Haven't tried that nor have we cleaned the sender floats since we bought the boat but all was working fine on holding tank mode then we switched to overboard for tiddly waters when all the pipework was replaced and the diverter fitted, 3 years back. My lovely lady does find the pump routine difficult even though the Jabsco manual Twist n' lock is about as simple as it gets. I wonder if the diverter has not fully opened and has blow by to the tank or maybe the tank breather is clogged?