overflowing head

[John]

The forward (electric)head on my 1991 Hunter 42 was filling up and overflowing after flushing. THis started suddenly with no other symptoms that I am aware of in the two weeks that I've had the boat. The seacock was frozen in the open position so I removed the seawater intake hose between the PAR pump and the top of the bowl and plugged it. Fixed the problem, and subsequently I replaced the entire pump mechanism. Works fine now but I'm perplexed as to why the head overflowed... there apparently is a vented loop in the seawater intake line, since when I was replacing the pump, removing the intake hose produced no water flow. I guess that there is some kind of a siphoning effect taking place? Any ideas as to why and how to fix? Could it be that the vent to the holding tank is clogged (I'm away from the boat this week and didn't think to check that possibility) and it was drawing water through the loop and into the head? Running the macerator did drain the water in the head when it was filling up...... or could it be that there is pressure in the holding tank that was forcing water back into the head and overflowing? Help!

 

[Peggie Hall/HeadMistress]

The head overflowed because...

...your toilet is below the boat's waterline, the seacock was open, and the dry/flush valve in the toilet pump had failed. Water outside your boat was simply seeking its own level inside your boat. Not good. And if there's only a short piece of hose between the pump and the bowl, there is no vented loop in the system...if there were, it would be obvious, not "apparent," because a vented loop is a 180 degree arched fitting (there are photos of 'em in the West Marine, BOAT/US etc catalogs) that would be at least a foot above the toilet, with hose going up to it from the pump and another one coming back down to the bowl. I don't THINK you could miss it.Put one in. And do whatever it takes to make that seacock operational...'cuz (all together now class): all seacocks should always be kept closed except when actually in use. And you've just seen the reason why. Since replacing your toilet pump assembly, you're relying solely on a valve in the toilet that you already know can fail to keep your boat from sinking... In fact, Jabsco has recently had a whole rash of failures due to defective valves, so you can't just assume that yours won't because it's new. So install a vented loop, fix the seacock--and any others that don't work. And keep 'em closed except when you're actually using whatever's attached to 'em.

 

[john]

overflowing head continued

Peggy,Thanks for the quick response. Your recommendation was my initial thought and the seacock is next on the worklist.But the part of the explanation that I can't reconcile is that when I disconnected the head pump from the raw water intake and let the hose just sit on the floor of the head, no water flowed. I had expected a large gushing flow if there was an open, below-the-waterline path to the thru-hull.So I guess my next call is to Hunter to try to understand how they engineered/installed the hose and head - with the key questions being is it below the waterline and is there, hidden behind the cabinetry, a vented loop for each head feed? Thanks again.