Grey water sump issues ( boring stuff only for duckowners)

South Pacific Familyadventure 2008
Claes Brodin
Sat 15 Apr 2017 19:02
The forward head sink and galley sink are both drained with through hulls. In the aft head grey water from shower and sink is drained into a sump with a floatswitch connected to a Gulper 320 sump pump. Not noticing an intermittent failure of the floatswitch grey water leaked into the aft bilge and subsequently engaged the aft bilge pump (through another floatswitch). Due to a failing checkvalve(frozen in a locked position) installed on the bilgepump, water in the aft bilge was just sloshed around. Fortunately I was onboard noticing and could switch off the bilgepump. If this would happen with no one onboard batteries would have been drained out.
As I understand from Randal these floatswitches with the time needs to be replaced. In this case a failing floatswitch in the grey water sump could through a chain of events have lead to completely drained batteries from an engaged non working bilgepump.
It raises two questions
-Should the bilge pump really have a checkvalve installed?(Rule company themselfes advise against it)
-Is this complicated grey water sump setup really a better solution than draining grey water as in forward head and galley sink, via through hulls.Avoiding another through hull and the vague environmental reasons for a grey water sump are not arguments enough to me.

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