Strange vacuflush issue - pump keeps running despite replacing almost everything

carterchapman said:

Try to call Marine Sanitation (marinesan.com). I have had them answer a lot of questions, and perhaps they can tell you the size of that donut...

Click to expand...

Thanks for the lead.

May need the tester...
https://marinesan.com/dometic-vacuum-tester/
Sounds like your not getting enough vacuum to satisfy the switch and you have a leak somewhere.
Looking forward to your success.

Working on a friends this past weekend for similar issue... but his won't flush as if something has the hose stopped up from the toilet. Took his bellows out and there was a slight deformation in the bellows, but what looked worse was a thin film of what looked to be a calcium deposit (light brown in color) inside the bellows housing. We're thinking it's not building up enough pressure to clear the hose. He has ordered a new bellows and housing, duckbills, and O-rings. We will rebuild this weekend and see if it clears.