Fresh water toilet flush
Flushing toilets with sea water generates a layer of calcium inside the discharge tubes. This gets quite thick over time. It blocked the discharge tube in the owner’s cabin (we have three cabin version) after 18 months. It’s a shitty job to solve. Biggest problem is in the non-return valve close to the holding tank. If cleaned in time you have less of an issue. You can dismount the last meter of discharge tube together with the non-return valve and clean it outside of the boat.
Anyway, it appears that flushing with fresh water reduces the calcium problem.
There is a very simple way to modify the toilet in the owner’s cabin to flush it either with fresh water or salt water (when fresh water is scarce). Fit a T-connector between the water tank and the fresh water pump. Fit a 3-way valve between the sea water intake and the toilet pump. Connect a hose between the T-connector and the 3-way valve. Done. See sketch.
Hi yet again
With this setup there is a non-zero possibility of head water leaking into the main tank, very bad.
A better setup is to T the sink drain hose into the raw water inlet close to the hull. Now all you need to do is fill the sink with fresh water (or gray), let gravity do its thing, and flush.
Credit: Peg Hall
The flush water comes in the bowl under the edge of the bowl. There is no way anything in the bowl can flow back through those holes under the edge. Even not if the bowl overflows. The waterpump will not let the water run back. Water tank is way above the pump and toilet. So there is always a higher pressure on the tank side of the pump than on the bowl side.
Did you feel the need to add a solenoid anywhere? Or did the T-Valve take care of it? Assuming you did this for each toilet?
Quick question – we just bought a Saona 47 as well (non-owner’s version), assuming this is being done where the water tank + pump are in the anchor locker up front, correct?