Bill I think you’re completely correct with your conclusion about the three way valve. Many thanks for that great tip !!!
I’m having long time the same problem as David. Only difference is that I’m having a manual shut off valve ( grey/blue valve on the picture ) in the fresh water line before the three way valve.
That one I always shut off manually to get rid of the problem that the fresh water pump goes on every 20 minutes.
But to run the watermaker I need to go in the engine room to open that manual valve to allow the watermaker to do a flush after use. When ready I need go in the engine room again to shut the same valve.
I thought that the only culprit to this problem was the solenoid valve.
Asked the Dessalator dealer here in La Rochelle to check it but he could not solve the problem. Asked the Amel crew on the Amel pontoon which also had a look but couldn’t find the cause.
Went back to the Dessalator dealer and he told me it could be some calcium on the solenoid valve which blocked it from closing completely.
He advised me to order a new one. Which I did.
Installed that new valve (by coincidence yesterday) and the problem was still there !!
Today I read your remark about the three way valve.
I closed that valve (horizontal) left the manual grey/blue valve open and to my surprise problem was gone !
Which mean that your correct, the fresh water was simply leaking via the three way valve back to the seawater intake. And NOT via the solenoid valve !
I never thought about that possibility. Not only me … but also not the Dessalator dealer and also not the Amel crew on the pontoon.
Again big thanks for the great advice !!
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