In line no return valves

[ShipsWoofy]

At the end of last year I fitted no return valves to each of my bilge pumps. A few months ago the stbd pump stopped pumping overboard. Suspecting the new valve I disconnected the pump and blew down the pipe, a pop and the valve unstuck and all is still well.

This weekend the port pump did the same thing, so I disconnected the pipe and blew down it. There was no blockage that I could feel. I removed the valve and blew and sucked, it works fine (seemingly). (Please no dirty minds!).

Putting the pipe on the pump without the valve is working fine. So here is where I am at. The valve is made up of rubber sectors which open one way and close the other, thus preventing the water in the pipe flowing back into the bilge.

Is this normal that they jam, is there a way to lubricate them, should I take them back out of the system? I have heard people say you should not use them.

 

[tugboat]

Lets assume you've fitted them the right way round (ducks behind something solid!) I also assume these bilge pumps are the electric type, as manual pumps already have these valves and you wouldn't need extra n-r valves in the line. I have only ever used these things once, for an electric pump on a monohull which when well-heeled allowed water back down the line. As you are a cat-man, why do you need them. If your discharges are too near the waterline, could you not incorporate a swan-neck of hose which would serve the same purpose for a multi. Regarding the n-r valve itself, if it is the 3-pointed star arrangement there should be gaps between the rubber flanges when it is at rest so it shouldn't stick together.

 

[Joe_Cole]

I've never had a problem with mine, which makes me wonder if perhaps you've got something sticky in your bilge water?
FWIW I would try silicon grease on the valves.

 

[ShipsWoofy]

I use them to prevent that 1/2 pint of water in the pipe returning back into the bilge when the pump is switched off. The outlets are far enough out of the water not to cause us problems such as suffered by you half boat sailors.

The weird thing is, as I suggested, when blowing down the valve it did not appear blocked, it did not take a lot to open the valve. It is the segmented type as you suggest.

Will try a little smearing of silicone grease and see if that frees it up a bit.

Cheers.

 

[fireball]

We've got one for exactly the same reason you state - 1/2 pint of water sloshes around in the bottom and I prefer a dry bilge - not stuck yet - but one to bear in mind!! /forums/images/graemlins/smile.gif

 

[philmarks]

I've got four of the blighters on my pumps' outlet manifold, and they all stick or dribble back slowly. Yesterday I went out and bought conventional lever valves. Not ideal as I have to open a valve before using a pump. C'est la vie.

 

[yerffoeg]

What make is the non return valve? Is it a plastimo? I am needing to fit something similar this year and may consider an alternative make!

Rgds
Geoff

 

[tugboat]

Might be worth considering that the tiniest piece of debris sticking to the grease would stop the valve closing properly and therefore it couldn't function as intended. Not that I'm suggesting your bilges aren't squeaky clean, of course! /forums/images/graemlins/blush.gif

 

[TFJ]

I have a similar problem, when I switch the bilge pump on the water is pumped out without a problem until the water level is at or below the pump base, if you leave the pump running and water (from my water tank when draining) is still coming in and the pump still running the pump will not pump water out until I turn off the pump and turn it on again then it works as normal, then again the process starts all over again - any ideas
I am going to LIBS and ask the question but any help would be appreciated

 

[Ships_Cat]

Just a possibility - I ran into a similar problem with an electric pump on a new build, but there was a non return valve up by the thru hull fitting. Your installation may not be the same.

It was cured just by taking the non return valve out as it was kind of redundant. Didn't really investigate further but was related to the valve being held shut by the column of water above it and the pump airlocking when it sucked air. Stopping the pump allowed it to flood again.

If the pump is switched by an external float switch, lifting the float switch a little may help (regardless of whether there is a non return valve further up the line or not).

John

 

[TFJ]

John
Thanks for your help, I don't have a float switch but can see how a non return valve could have water above it and stop the unit pumping water out, I will see what the manufacturers say and let you know
Terry

 

[philmarks]

I have a range of different ones - I think one type is EC Smith, another plastimo. Will have a look later when I'm removing them /forums/images/graemlins/smile.gif

 

[Guest]

A better alternative ...

Most chandlers sell the GFN plastic non-return valves that are cheaply produced and often leak back, stick etc...... in my view generally rubbish ...

I have various pumps in one of my lines of biz and use brass bodied garden / domestic non-return valves .... yep garden NR valves !! They are constructed from high grade brass with a proper moving pin fitted with stop flap in hard plastic ... held closed by a light spring. The spring being just enough to close the valve making sure the back flow then keeps it shut. A small amount of pressure / flow is sufficient to open it fully and I have not had sticks in the year that all have been in use - and I pump chemicals, fuels and all sorts through them. The fact of debris causing a back-leak is a fact of life with NR valves and a quick back-flush is all thats needed with these.
Out here in baltics a 3/4" NR valve as above is about £2.50 .... end connectors to fit various hose sizes - pair would be about another £2 .....

Why buy rubbish when you can get a good one ??

 

[Guest]

Problem with grease

Greasing an item such as this could actually lead to more trouble than it cures ..... oiling it with a little castor or cooking oil maybe .... same as you do with a sea-loo, but grease ? that will catch any sediments / crud that is pumped and could keep the valve open ....