Does anyone know how to access the vented loop for the main/aft head in a H40.5? I am thinking about replacing the vent to prevent backflow and for ease of operation. If you've seen my other post today...it seems I am having vented loop issues all over the place on my boat. Thanks for the input! s/v CATALYST
Aft head vented loop
- Thread starter WuWei28
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Facing the head, look up atop the mirror on the left. You will see a a small panel, maybe 6X8" in the left side. Remove the trim covers to access the screws and remove the panel. RD PS: it is unlikely you need to replace the loop for any reason having to do with toilet operation. You probably need to service the vent on top to remove the salt build-up, but it won't affect the head operation much. More likely, you need a new head pump and joker valve. I replace my heavily-used one every year to two. I wouldn't mess with rebuild kits, especially if it is a Jabsco (which mine is). They do not rebuild well.
Facing the head, look up atop the mirror on the left. You will see a a small panel, maybe 6X8" in the left side. Remove the trim covers to access the screws and remove the panel. RD PS: it is unlikely you need to replace the loop for any reason having to do with toilet operation. You probably need to service the vent on top to remove the salt build-up, but it won't affect the head operation much. More likely, you need a new head pump and joker valve. I replace my heavily-used one every year to two. I wouldn't mess with rebuild kits, especially if it is a Jabsco (which mine is). They do not rebuild well.
Vented loops in heads....
I'm beginning to think that that 90% of boat owners don't have a clue about what a vented loop does. A vented loop in the head discharge line has nothing to do with the toilet's operation...it's only function is to prevent sea water forced UP the head discharge thru-hull from starting a siphon. Since you can only flush into a tank in your waters, you don't even need one. The head intake is another matter...the vented loop in the head intake line still doesn't affect the operation of the toilet, but if the bowl or any part of it is below the waterline, it is needed for two reasons: 1) to break any siphon started by priming the pump...2) to put an arch in the line that's well above the waterline to prevent flooding the bowl and even sinking the boat if the thru-hull is open and the wet/dry valve is either left in the wet mode or fails. Neither vented loop will prevent backflow or have any effect whatever on how easy or difficult the pump is to pump. Backflow happens when the toilet isn't flushed long enough in the dry mode to move bowl contents all the way over the top of a loop..what's left between the top of the loop and the toilet is gonna run back downhill. And if the joker valve (a one way valve in the toilet discharge) is worn, whatever runs downhill will end up back in the bowl. So the cure is: pump longer in the dry mode, and replace the joker valve at least once every two years...annually is better. A pump becomes hard to pump and squeaks because it needs lubrication...the seals and o-rings are rubbing unprotected against the inside of the cylinder wall. The cure: lubricate the pump. It's easy to do...in fact, I just posted instructions a day or two ago in another thread. You might want to check out the link below to learn how marine toilets work and how to maintain 'em.
I'm beginning to think that that 90% of boat owners don't have a clue about what a vented loop does. A vented loop in the head discharge line has nothing to do with the toilet's operation...it's only function is to prevent sea water forced UP the head discharge thru-hull from starting a siphon. Since you can only flush into a tank in your waters, you don't even need one. The head intake is another matter...the vented loop in the head intake line still doesn't affect the operation of the toilet, but if the bowl or any part of it is below the waterline, it is needed for two reasons: 1) to break any siphon started by priming the pump...2) to put an arch in the line that's well above the waterline to prevent flooding the bowl and even sinking the boat if the thru-hull is open and the wet/dry valve is either left in the wet mode or fails. Neither vented loop will prevent backflow or have any effect whatever on how easy or difficult the pump is to pump. Backflow happens when the toilet isn't flushed long enough in the dry mode to move bowl contents all the way over the top of a loop..what's left between the top of the loop and the toilet is gonna run back downhill. And if the joker valve (a one way valve in the toilet discharge) is worn, whatever runs downhill will end up back in the bowl. So the cure is: pump longer in the dry mode, and replace the joker valve at least once every two years...annually is better. A pump becomes hard to pump and squeaks because it needs lubrication...the seals and o-rings are rubbing unprotected against the inside of the cylinder wall. The cure: lubricate the pump. It's easy to do...in fact, I just posted instructions a day or two ago in another thread. You might want to check out the link below to learn how marine toilets work and how to maintain 'em.
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