Originally Posted by philarick
Just bought a Four Winns Vista 348 and the vacuum pump keeps activating every 10 minutes or so. It cycles a few times, then shuts off. 10 minutes later it does it all over again. Head flushes fine.
Leaking duckbill valves are the most likely reason for the pump cycling for no reason between flushes. There are 4 duckbill valves in the vacuum pump--two on the inbound side, 2 on the outbound side. All four should be replaced every couple of years because--like joker valves in other toilets--the slits become stretched with use and cease to seal completely, creating an air leak. A drop in "vacuum" turns the pump on long enough to restore it.
You need a trouble shooting guide, which is in the owners manual. The V/Flush has changed so little except cosmetically since it was first introduced by Mansfield Plumbing
in 1978 that age and model (model only applies to the bowl) doesn't matter...the same trouble shooting guide applies no matter which one you have. I've saved it to a PDF that I'll be glad to send to you or anyone else who'd like to email
me (EMAIL, not a PM)...and I'll also attach a piece I wrote called "VacuFlush 101" that should help you reduce the need to trouble shoot it considerably.