bilge pump check valve

[Scottster]

I just bought my 2004 340 Sundancer a couple of weeks ago. I was down in the bilge this weekend looking around and checking oil levels etc. I noticed there was a blue valve in the aft bilge pump line that goes overboard. The valve was hidden by the blower ducting. The valve was broken in several pieces so I removed the entire thing. I got home and stumbled on a thread that addressed this very issue, but didn't really have any conclusion. Should I replace it or just leave it out? Is there a better valve to install. Any advice? I don't think the more forward bilge pump has this check valve.

 

[Lazy Daze]

If your bilge discharge line has an upward loop in it right before it attaches to the thru-hull, there is no "safety" reason to put it back in. All that's going to happen is the water that is in the discharge line will back flow back into the bilge when the motor shuts off. If you don't mind that little bit of water coming back in, then don't replace.

 

[tobnpr]

It's necessary only if there's enough "backflow" held in the line that it triggers the bilge pump again when it runs back to the sump.
In that type of situation, it needs to be installed or the bilge pump will continually cycle in an endless loop...

 

[Lazy Daze]

It's necessary only if there's enough "backflow" held in the line that it triggers the bilge pump again when it runs back to the sump.
In that type of situation, it needs to be installed or the bilge pump will continually cycle in an endless loop...

Your hose must be extremely long:smt001

In reality, how much is probably in that hose? 1 gallon?

 

[Southpaw II]

What typically happens is that water in the line freezes and breaks the valve. These are located near the outside of the hull, which is one of the coldest places on the boat during the winter. The fact that there is an open passageway to the outside where there is cold air doesn't help. Be sure and vacuum up all the small broken pieces so that your bilge pump doesn't get clogged.

 

[tobnpr]

Your hose must be extremely long:smt001

In reality, how much is probably in that hose? 1 gallon?

Yup, it is ...
I'd bet the line from the forward sump, which runs across to the stbd side and then to the rear of the cockpit is easily fifteen feet long. A gallon of water (if it is that) would def be enough to raise the switch to the "on" position again from it's position after shutoff.

Since they restrict flow, it's always best not to have one if you don't need it.

 

[Scottster]

Thanks guys. I think I will try to eliminate the valve. I understand that it might continously operate when the line backflows. I might experiment with that and see how much water it takes to raise the float.

I bet that is how it broke. It had water standing on the valve suring the winter and it shattered.

Thanks again.:thumbsup: