Hi Jim: I'll look again. Maybe you're right. The dealer from whom I got these made a big deal about the backflow issue but that was a year ago and I might be confused. Thanks Joe PS: I'll report on the success (or lack of) of this experiment into the unknown on TWL. In-so-far as I can determine, no one on TWL has ever used this system. Phase 1 (almost complete) is to use their toilets, plumbing, air supply and etc. set up to dump into our existing SANX MSD treatment system. They use so little water compared to our existing Crown toilets that we should get a lot more flushes that way. Phase two: will be to remove the SANX and use the Microphor digester as the MSD. That's the one I am nervous about. One committed to their system it will be a big problem to go back if their MSD digester does not work out. But, I have talked with many tugboat owners around these parts that use this same system and they report no problems. Its a little overkill for our 40 ft boat. It is really designed for larger vessels. However they made this smaller system for smaller boats and on paper, it should be OK. If it all works, it will be nice to have a system that meets all of the no discharge rules but does not require a pumpout. Joe Engel Portland -----Original Message----- From: Jim Fidler [mailto:fidlerjim@earthlink.net] Sent: Thursday, August 14, 2003 9:48 AM To: trawler-world-list@lists.samurai.com Subject: TWL: Re: backflow preventer for sewage system - products? Joe Out of curiosity, I looked at the Microphor website. Interesting toilets. It looks to me like you don't need to add anything. The toilets include a vacuum break on the flush water valve. That should provide backflow prevention, shouldn't it? This looks similar to the VacuFlush toilets. There is a vacuum break in line with the flush water and located just a few inches above the top of the bowl. They connect directly to the pressure water system without any additional devices. Jim Fidler "Fiddlesticks" ---------------------------------------------------------- According to ABYC I will need to use some kind of backflow preventer system. Will a simple siphon break suffice or do I need to use some other device and if so, what? Joe Engel _______________________________________________ http://lists.samurai.com/mailman/listinfo/trawler-world-list To Unsubscribe send email to trawler-world-list-request@lists.samurai.com Include the word "Unsubscribe" (and nothing else) in the subject or body of the message.