Bilge pumps and non-return valves

[airborne1]

Would appreciate opinions/advice on fitting non-return valves to bilge pumps.
I have two Whale bilge pumps installed at the bottom of my bilge which do a very nice job of emptying the water. Unfortunately they are lifting the water approxiamately 3 ft up a 1" pipe to the overboard outlet. When I switch off the pump(s) when they are sucking air the water remaining inside the pipe then floods back and re-settles into the bilge. This is more annoying than anything else.
Question: Should I fit a one-way (non-return) valve in the outflow pipe so that the water in the pipe can't flood back or is there some drawback to this.

 

[peteandthira]

I put up with it and mop out the last bit occasionally. However, thats with quite a dry bilge and the wetness is usually there because I put it there (to test the pump for blockages).

 

[Guest]

Why not .... shouldn't cause trouble. Other way is to stop air entering discharge line by having a manual valve at outlet.

Only problem with NR valves are the tendency to get bits in and then they don't close the flap properly ... leaving a small gap ....

For the above reason - they should never be trusted to provide water-tight seal.

 

[fireball]

We have the same issue - I put a NR valve in - but it makes no difference because it still weeps - so just takes longer to seep back to the bilge ... so we have to mop it out occasionally instead.

 

[Malish]

my pump (a large Attwood) didn't like the addition of a non-return valve and stopped lifting water. If you are considering fitting one I would urge you to test your system after installation.

 

[AlanPound]

We now have two bilge pumps - the original, a big one with a float switch is a little off the bottom (it never removed everything anyway), it has the biggest diameter piping I can fit, and exits via the original skin fitting...

The new one is a small one on a manual switch, and is as close to the bottom of the lowest part of the bilge as I can get it. It has a fairly small diameter pipe to minimise the water it can contain, and has a non-return valve close to the pump. Basically, I use that one to pump out 'odd' small amounts of water, as and when....

The big one is the serious one, and should always be ready to work automatically, unimpeded (and yes, I do test it from time to time...)

 

[pampas]

Yes to fitting one, stand the pump/ suction pipe in a stainless flour sieve and tha will stop the valve from jamming and is easy to clean.

 

[ColinHuggins]

[ QUOTE ]
We now have two bilge pumps - a big one with a float switch . . . and a small one on a manual switch

[/ QUOTE ]

That's why I added a third one: no switches, just a handle and Armstrong's Patent. It works even when the battery's flat . . .

 

[vyv_cox]

I have a non-return valve in my shower drain but, as said above, it doesn't work well. It also reduces the efficiency of the pump, which I see from the recent YM test, is the least efficient they tested! So I intend taking it out again.

 

[Guest]

The only good non-return valve is in its box un-used !! OR ... a manual valve that you open / close !!

 

[ShipsWoofy]

Don't do it.

I fitted two of those in-line rubber flap type, one in each hull.

I was very pleased with my self when the pumps pumped and the water stayed in the pipes.

Within months the starboard one jammed closed, the pump just couldn't push past it. A few months later the port one jammed exactly the same, the port bilge is always much cleaner than the starboard, so this was not oil or such, they just jam.

I have them both in a locker on board, you can have them if you want, but I will not be held responsible if anything happens to your boat.

You would be better fitting float switches and living with an inch of water and mopping up when you get there.

DO NOT FIT ONE WAY VALVES TO BILGE PUMPS <span style="color:red"><span class="small">you can quote me on that</span></span>

 

[ColinHuggins]

Re: Bilge pumps - he says NO . . . .

. . . and I say YES!

They came with the boat, fittel to all three pumps, tiddly Whale things the size of half a cigarette, wouldn't know they were there, no probs.
And a pipefull doesn't drain back into the bilge of course.