The bottom part of our icebox is getting filled with salt water from the drain opening. This seems to be coming from the through hull being open. We have an electric pump installed by the PO to drain the ice box. How can we stop the salt water from coming in when we want to leave the through hull open to use the sink? We always thought this was fresh water resulting from the ice building up on the refrigeration but we left the fridge off and drained it out and there was still water entering. Then we realized that it was salt water.
Also, when this water accumulates (about 3-4 inches) there is water draining from somewhere under the starboard side of the ice box down into the bilge. Is this some hose clamp loose that we can't see or could there be something with a crack in it leaking?
Our icebox wastewater is plumbed to the sink.
The pump shouldn't backflow. You could install a vented loop above the waterline, but the easy answer though is stick a cork in it. Seriously, a rubber plug in the drain fitting at the bottom of the box does the trick.
I had put a ball valve at the external drain exit of my icebox. Only opened it when needed.
I just drain mine into the bilge because the foot pump broke. To prevent sink/sea water from entering the fridge, there was a one way check valve in the line.
Sue : I'd recommend a simple garden hose ball (On/Off) valve. Open when you need to drain/clean and Closed otherwise.
Reason - is that check valves will get stopped up and fail when any "junk" get caught in them!!
A thought
My factory setup includes an electric pump. Ball valve between the ice box and the pump inlet, another ball valve between the shower drain and the same pump inlet. There is a separate thru hull to serve this pump. No connection to the sink whatsoever.