Bilge outlet pipe keeps blocking

[Ric]

I have a problem with one of my bilge outlet pipes randomly blocking. Everything works fine for a while, then suddenly I will find the pump whirring away but not pumping. If I disconnect at the upstream end of the check valve I cannot blow through the check valve. If I disconnect the check valve at downstream end, water evacuates from tube and then I can easily blow through. I can also easily blow through the disconnected check valve. What is going on?

Could it be that the check valve is jamming shut?

 

[RichardS]

The one-way valve seems to be working correctly but most bilge pumps will not pump air so have to be fully immersed to work. This means they always "run dry" with some water still in the bilges and the pipe up to the check valve still full of water which runs back when the pump stops.

If your pump does not stop when it starts to run dry it sounds like a fault with the float switch.

Richard

 

[VicS]

I have a problem with one of my bilge outlet pipes randomly blocking. Everything works fine for a while, then suddenly I will find the pump whirring away but not pumping. If I disconnect at the upstream end of the check valve I cannot blow through the check valve. If I disconnect the check valve at downstream end, water evacuates from tube and then I can easily blow through. I can also easily blow through the disconnected check valve. What is going on?

Could it be that the check valve is jamming shut?

You dont say what make or type of pump. Impeller, diaphragm, flexible vane, submersed or not ???????

You dont give any indication of the lay out. Distance the pump has to lift water if it's not a submersed. Height of discharge. Location of check valve relative to pump etc.


The head of water in the discharge pipe may be sufficient to prevent you blowing through it until it is drained. If may also be preventing the pump from priming.

In some cases pump manufacturers state that check valves should not be used.

Your check valve may indeed be sticking shut.
Maybe the level control needs attention, leading to the pump losing prime

 

[Ric]

I have a Rule 900 pump as my lower pump, controlled by a water-witch. The upper pump is a Rule 1500 with inbuilt float switch, and finally a Rule external float switch will start both pumps going. Both pumps go through Jabsco check valves. I am beginning to think the problem lies with the Jabsco check valves - they are flap type valves rather than tricuspid like the Whale check valves, and they seem very sensitive to getting blocked closed or open.

 

[Len Ingalls]

I have a Rule 900 pump as my lower pump, controlled by a water-witch. The upper pump is a Rule 1500 with inbuilt float switch, and finally a Rule external float switch will start both pumps going. Both pumps go through Jabsco check valves. I am beginning to think the problem lies with the Jabsco check valves - they are flap type valves rather than tricuspid like the Whale check valves, and they seem very sensitive to getting blocked closed or open.

Flap type check valves are known to act badly in bilge exhaust hoses & are not recommended.
Their main advantage is to stop the annoying run back of bilge water when pump stops.
If your bilge pump is operating on a daily basis,you will never attain the goal of a dry bilge desired by some. Live with it or find the source of bilge water.
The second purpose of check valves in any exhaust water line is to prevent in take of water when heeled. Poor design.IMHO
Raise the exhaust thru hull or put a "hump" in hose.

If you are not finding debris in check valve when the problem happens,then,as VIC said,your average bilge pump cannot pump enough pressure to overcome the weight of water trapped in hose by the flapper.

Hope this helps / Len

 

[VicS]

I have a Rule 900 pump as my lower pump, controlled by a water-witch. The upper pump is a Rule 1500 with inbuilt float switch, and finally a Rule external float switch will start both pumps going. Both pumps go through Jabsco check valves. I am beginning to think the problem lies with the Jabsco check valves - they are flap type valves rather than tricuspid like the Whale check valves, and they seem very sensitive to getting blocked closed or open.

Presumably that is a LP 900 D if you are using an external controller.

The promotional literature and video indicate that the LoPro pumps have a tricuspid valve . It's not clear if that has always been so or if its a new feature that could be retro fitted to older pumps. If a tricuspid valve is fitted then an additional flap type check valve should not be necessary.

The installation instructions for the Rule Mate automatic submersible pumps indicate that they should not be fitted with a check valve!

 

[Ric]

Presumably that is a LP 900 D if you are using an external controller.

The promotional literature and video indicate that the LoPro pumps have a tricuspid valve . It's not clear if that has always been so or if its a new feature that could be retro fitted to older pumps. If a tricuspid valve is fitted then an additional flap type check valve should not be necessary.

The installation instructions for the Rule Mate automatic submersible pumps indicate that they should not be fitted with a check valve!

My pumps definitely do not have inbuilt check valves. They are a few years old though, so maybe an older version. Anyway, I am going to change the Jabsco flap valves for Whale tricuspid and see if that fixes the problem.