Plumbing Question for the Faithful

[Dave Kosh R.I.P.]

My new head pump works fine for the toilet except now I have some type of syphoening going on. Yep got water coming in at a trickle with a brand new Rariton toilet when it is off. Noticed it only when I'm running. Not a good thing filling up the holding tank in a jiffy. Do I need some type of anti-syphoening loop or check valve in the line between the sea cock and pump? If so what works well?
Dave K

[In Memory Walter K]

Yes, you have to check several things. Loop your water hoses to a point above your water line. There are reverse "U" fittings with release valves on the top that break the suction you create when pumping. Cut the hose at that high point and insert the fitting/valve with clamps and secure so it does not slip below the waterline in a bumpy sea. I'm sure most head installation diagrams show (or explain) them. They may be an optional item as bigger boats with toilet installations above the waterline may not need them. Walter

[IRGuy]

Dave...

Two things I would check on, having just installed a new Raritan manual head and holding tank in my 33.

The installation manual says to install a loop with a siphon breaker at the top, if the top of the bowl is below (or even near, IMHO) the water line, as siphoning can occur and overflow out of the bowl and fill the boat if the top of the head is below the water line.. and...

I read somewhere a while back about installing a generator where the guy had installed a scoop strainer over the thru hull fitting for his raw water cooling.. when underway the scoop caught water and drove it backwards through his exhaust system into his genny when it was not running, which hydrauliced the genny engine. If you have a similar strainer on your head intake this might be the cause of your water flowing while underway but not at the slip.

[Dave Kosh R.I.P.]

Yes I have a similar strainer now in the intake. I had no striner with my old head and had no issues. Should I just remove the intake strainer or unstall a vented loop or an unvented loop? I'm no plumber but me no like leaks like that. I shut the seacock off after I seen that. Dave K

[Dave Kosh R.I.P.]

Yes again the thru hull was replaced with the scoop type , bronze that I had left over from a generator project. I'll try the loop vent for anti suction.
If that doesn't work I'll remove the thru hull with the regular type like the original. Good thing my 31 is on a lift. Dave K

[IRGuy]

Dave...

I would try the antisiphon device in the suction line first.. no need to haul the boat for that, and see if it works.. My concern would be that even if it breaks the siphon when the boat is at rest the pressure of the scoop catching water and driving it through the head might be so great it would still force the water into the head or holding tank when underway.. if the loop/antisiphon vent does not work I would then remove the scoop strainer and replace it with a round strainer.

Frank (IRGuy)

[Dave Kosh R.I.P.]

Just got an email back from Raritan and they indicated that the vented loop must be placed on the output of the pump to the input to the bowl otherwise the pump will never prime. It will suck air. Gee I should of left well enough alone but when you have a seacock that shows signs of rot you replace it. So better off with a regular sea cock in this application folks also for a genset too as it is amazing how much water these little scoops will pick-up while you are running. Dave K

[IRGuy]

Now that I read your post above I realize that they are right, of course.. I looked at putting an antisiphon vent somewhere in my raw water feed line to the head but did not do it after I realized the top of my head bowl is above the water line. I was concerned about water siphoning into the head and overflowing the bowl while at my slip, and not while underway. I suppose it is best to keep the seacock in the raw water line closed when you are not on the boat anyway, just in case a hose or fitting had a leak.

As far as the scoop strainer picking up water is concerned.. consider how much pressure there must be driving water into the forward facing scoop at 20+ knots.... and the rubber duckbill check valves are of no help since they are installed to allow water to flow into the head, not prevent it from entering.

[Dave Kosh R.I.P.]

Yes sir IRGuy,
Just got another email back from Raritan (excellant service) and they said it is not necesary to replace the scoop . Simply turning it around backwards will work fine. Now I know why I'm not in a 65 Bertram and only a 31. Gee this board if full of good information. So you can use the scoop type but install them backwards to avoid the problem I just had.
Dave K

[IRGuy]

Dave...

If you were in a Bertram 65 you wouldn't have this kind of problem, because one of your lackeys would be doing this kind of work for you!

Frank

[Capt. Mike Holmes]

Capt. Dave, I just installed the top of the line Raitan - the one that looks like a household toilet and flushes on a timer. This is my 3rd electric head since I've owned the boat - theit had a manual flush head whn i bought it that was toast. I guess my raw water inlet line does make sort of a loop by the time it goes through the cockpit sole and to the inlet on the head, but it was not by design. My head is on a raised platform I installed, not sitting on the floor, so it is considerably above the waterline, and on this model the raw water inlet is quite high, anyway. Have no problems priming. I have a regular round thru-hull, and have never had problem with water entering while underway unless the pump was running.

[Dave Kosh R.I.P.]

Thanks gang. I think now we all know more about heads. Mine is also on a pedestal riser. Good things to know especially since this is one of the most common ways boats sink by faulty head plumbing. My other Raritan lasted many many years. New one really flushes good, just like home. No clogs. Beats the 5 gallon bucket or porta potty! Dave K