how high the loop ?

[gbendaly]

hi there
this is a question related to the plumbing system in the heads.

the loop of the discharge pipe runs very high inside a locker in the heads compartment ,almost 90 to 100 cm, I keep having a smelly "water return" rushing back in the bowl, I assumed this is due to either a defective one-way valve in the pump,or maybe the over-raised vent loop..
before I dismantle the pump unit and undertake the replacement of this valve, I wonder if it helps if I lowered the loop first ?? and what would be the recommended height??
thanks

[Paul Elliott]

This is an anti-siphon loop, so the loop and vent should be above the heeled water line. If not, the water could siphon in from the through-hull (a very bad thing). The vent is usually connected to the outside air via a small tube to keep head odors out of the cabin.

You need to pump enough clean water when flushing to push the dirty water over the top of the anti-siphon loop.

Does your head feed directly into the holding tank? If there is no way for seawater to siphon back in, you may not need such a high loop. My head can be valved to connect to the through-hull, so I definitely need the high loop.

[hmsindy]

You probably need to replace the joker valve...

[Chief Engineer]

And don't eat corn on the boat

[gbendaly]

Originally Posted by Paul Elliott

This is an anti-siphon loop, so the loop and vent should be above the heeled water line. If not, the water could siphon in from the through-hull (a very bad thing). The vent is usually connected to the outside air via a small tube to keep head odors out of the cabin.

You need to pump enough clean water when flushing to push the dirty water over the top of the anti-siphon loop.

Does your head feed directly into the holding tank? If there is no way for seawater to siphon back in, you may not need such a high loop. My head can be valved to connect to the through-hull, so I definitely need the high loop.

I have removed and eliminated the holding tank as it was a subject of disagreement between the mrs and me ,,,odors and such .. so we decided to use the marina toilets when tied to the pontoon and directly flush in the sea when cruising...

[Southern Star]

gbendaly, I gather when cruising you don't anchor out, or use the head when close in to shore. Even then, in North America (and I suspect many other places), you'll be hit with a substantial fine if you are ever boarded for an inspection.

Brad