Toilet Syphoning?

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seumask

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When we are sailing in rougher weather usually F4 and above we find the toilet ( Brydon par) fills up over about an hour before it over flows. Clearly shutting the seacock would prevent this however I cant say I will always remember to do that and was wondering if it was worth putting a “siphon break “ on the high loop of the inlet pipe, are they easy to fit and do they work, any other comments!
 
Could be that the inlet valve is not sealing properly, and is allowing the inlet water to pass as the boat rolls. Check to valve it may cure the problem.
 
Top of the inlet loop should be well above the W/L when heeled to account for wave height and the pitching of the boat. The top of this loop should ideally have a syphon break. Never rely on the valve in the toilet alone.
 
It is also possible to drill a tiny hose ontop of the inlet loop. This prevents syphoning and saves a few bob on a valve. The hole will weep when toilet is flushed, but nothing dramatic. The hole can be tiny. The larger the hole the more water left in the pan after a flush. This is the system I use and never had a problem.
 
You jest, but in the Middle East - toilets normally come equipped with a "Shitofa" (Transliterated from Arabic) - a water jet in the pan that does just that!
 
Yeah! In fact isn't it interesting that it is only in the so called "developed world" that people don't wash themselves after pooping? You always see signs saying "now wash your hands" but after adopting the habit of washing bum afterwards in Japan, Thailand, and the Middle East I can't come to terms with the accepted habit of wiping off the excess with a piece of paper, then pulling up my trousers. Ugh!!
( too much information?)
 
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When we are sailing in rougher weather usually F4 and above we find the toilet ( Brydon par) fills up over about an hour before it over flows. Clearly shutting the seacock would prevent this however I cant say I will always remember to do that and was wondering if it was worth putting a “siphon break “ on the high loop of the inlet pipe, are they easy to fit and do they work, any other comments!

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There should be a vented loop in the intake--between the pump and the bowl, NOT between the through-hull and the pump, but first you need to understand what a siphon break does. Siphons are started by PULLING water through a line--by priming the toilet pump when you flush. A vented loop creates an air break that interrupts the flow. But a vented loop can ONLY break a siphon started by water being PULLED through a line...it will not prevent water from being PUSHED through a line, which is what is happening--In the "right" conditions, sea water is being forced up the intake line--and possibly the discharge line too--by the pressure of the hull against the water while underway.

Leaving the pump in the "dry" mode SHOULD block water from entering the bowl...if it doesn't, the wet/dry valve in your toilet has finally worn out (your toilet has be at least 20 years old...it's been that long since Brydon went of business). If it does still work, and you can't even remember to do that much, there's not much hope for you. If it doesn't, the only protection against a flooded bowl is a closed seacock. So unless you want to continue mopping up your head, program yourself--and instruct your guests--to always leave the seococks closed except when the toilet is actually in use.

There should be a vented loop in the intake--between the pump and the bowl, NOT between the through-hull and the pump--to prevent water from passively rising in the bowl when the boat is at rest if the toilet is accidentally left in the wet mode. However, relying on a vented loop--and especially a wet/dry valve--to prevent water outside the boat from finding its own level INside the boat when no one is aboard is the best way to sink your boat in its slip or on its mooring. So all seacocks should ALWAYS be closed when no one is aboard.

If your wet/dry valve has failed, unfortunately it cannot be replaced. The Brydon was a version of the Jabsco toilet, built in Canada under a licensing agreement. Jabsco continued to support it with parts till the early '90s...then with service kits only till about 5-6 years ago, then finally discontinued even the service kits. Very few parts now available for current Jabsco models will fit a Brydon. So it may be time to bite the bullet and replace the toilet. Even more unfortunately, the Jabsco toilets made today are nowhere near the quality of the Brydon--or Jabsco--made 20-25 years ago...average lifespan is now 5 years or even less. So if you opt to replace, now is the time to upgrade to a Lavac.
 
According to the Par Brydon instructions the syphon break (if fitted) should be between the inlet pump and the bowl, not between the seacock and the inlet pump, to avoid problems in priming the pump.

On many installations I've seen (including the brand new HR we chartered in Denmark) the toilet would gradually fill if the in/out valve on the toilet itself was left on 'in'. We always leave our own toilet set to 'out' even though our inlet piping should be safe from syphoning.
 
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