'05 Beneteau 393 has holding tanks mounted on bulkhead ABOVE toilets. Have tried several different (and expensive) backflow preventers inline, but still get backflow of dark water from holding tank. The manufacturers of backflow preventers say that the holding tank "should NEVER be mounted above the toilet" and that waste will always compromise the integrity of the backflow preventer, regardless of brand or type. Any ideas??
'05 Beneteau bulkhead mounted tanks backflow
- Thread starter Robert Buker
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I've never liked that system
And apparently you're buying backflow preventers that aren't made to be in contact with sewage. If you're seeing backflow after every flush--not just underway with a half full or more tank--it's not coming from the tank...it's waste/flush water left in the head discharge hose. The fix for that is easy: pump the toilet in the dry mode enough times to move the bowl contents all the way into the tank. Most people don't realize that any manual toilet that's working anywhere near specs can move bowl contents up to 6 linear feet and up to 4 vertical feet in the dry mode...so they never use the dry mode except for a few pumps to clear the last of the water out of the bowl. So if the head discharge hose runs uphill at all, the waste and/or flush water left in the line is gonna run back downhill into the bowl. Replacing the joker valve frequently will slow it down to slow seepage, but it won't stop it. Pumping long enough in the dry mode to move the bowl contents all the way to the tank will still leave a little water in the line...but only a cupful or less instead quarts. And, if you switch to the wet mode just long enough to bring in enough water to rinse out the hose, then switch to dry to pump that ALL the wat to the tank, that cupful of runback will be a lot cleaner. And by learning to use the dry mode to move bowl contents to the tank, you can double the number of flushes your tank can hold too. If you only have runback while heeled when the tank is at least half full, there are a couple of fixes for that...but I need more infomration to know whether any of 'em are practical on your boat. How much space do you have above the tank? Where is the inlet fitting on the tank--inboard or outboard?
And apparently you're buying backflow preventers that aren't made to be in contact with sewage. If you're seeing backflow after every flush--not just underway with a half full or more tank--it's not coming from the tank...it's waste/flush water left in the head discharge hose. The fix for that is easy: pump the toilet in the dry mode enough times to move the bowl contents all the way into the tank. Most people don't realize that any manual toilet that's working anywhere near specs can move bowl contents up to 6 linear feet and up to 4 vertical feet in the dry mode...so they never use the dry mode except for a few pumps to clear the last of the water out of the bowl. So if the head discharge hose runs uphill at all, the waste and/or flush water left in the line is gonna run back downhill into the bowl. Replacing the joker valve frequently will slow it down to slow seepage, but it won't stop it. Pumping long enough in the dry mode to move the bowl contents all the way to the tank will still leave a little water in the line...but only a cupful or less instead quarts. And, if you switch to the wet mode just long enough to bring in enough water to rinse out the hose, then switch to dry to pump that ALL the wat to the tank, that cupful of runback will be a lot cleaner. And by learning to use the dry mode to move bowl contents to the tank, you can double the number of flushes your tank can hold too. If you only have runback while heeled when the tank is at least half full, there are a couple of fixes for that...but I need more infomration to know whether any of 'em are practical on your boat. How much space do you have above the tank? Where is the inlet fitting on the tank--inboard or outboard?
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