Water pump cycling but there is no leak

[hd002e]

I have a shurflo water pump on my boat (see attached photo). The pump cycles every minute or so as if there is a water leak in the system somewhere. I checked the entire length but there is no leak. It is very annoying so I end up turning off the power. Any ideas what might cause this? I took it apart to see if the diaphragm is torn but it all looked clean. Thanks!

[Attikos]

Is it pumping out water, or when it comes on is nothing coming out the discharge outlet?

[SailRedemption]

It's probably getting past the diaphragm. It may look clean but it may be old and not sealing as it used to. Cheapest solution is to buy a rebuild kit so you can change the rubber impeller. If that doesn't work you have a leak somewhere you can't see or your pump is shot.

[boom23]

There is a one-way valve somewhere along the hose. It is most likely bad and it allows the left over water to drain back to the pump. Replace the valve and you should be OK.

[hd002e]

When I turn on the faucet, water comes out as usual. There is no one way valve in the entire system, I think it is pressure activated.

Makes sense about the rubber not sealing properly, I will look into a rebuild kit.

[boom23]

Originally Posted by hd002e

When I turn on the faucet, water comes out as usual. There is no one way valve in the entire system, I think it is pressure activated.

Makes sense about the rubber not sealing properly, I will look into a rebuild kit.

My ex Lagoon and current Beneteau have one way valves at the hose or at the intake strainer. The valves are there to stop the water coming in the boat from the outside. They also stop the problem you are describing. The pump cannot push all the water out of the boat. Whatever is left in the hose after the pump flows back in the bildge, if there is no one-way valve. This can make the pump cycle forever.

Just a suggestion... Look at the easy things first.

[hd002e]

Sorry if my post was not clear. This pump is the water pump for running water, not the bilge..

[boom23]

Originally Posted by hd002e

Sorry if my post was not clear. This pump is the water pump for running water, not the bilge..

Oops... My bad...

I would replace the torn diaphragm you found and see if the problem goes away. If problem is still there, check the pump manual for a troubleshooting section.

Good luck.

[wiekeith]

Originally Posted by hd002e

I have a shurflo water pump on my boat (see attached photo). The pump cycles every minute or so as if there is a water leak in the system somewhere. I checked the entire length but there is no leak. It is very annoying so I end up turning off the power. Any ideas what might cause this? I took it apart to see if the diaphragm is torn but it all looked clean. Thanks!Attachment 162783

I had a similar problem last year, which I appear to have resolved. On the rear of the unit is the switch mechanism that tuns the power on when the pressure drops, typically when a faucet is opened. The microswitch in the mechanism is operated by a small diaphragm. I removed it, cleaned it, put marine grease on the edges where it seals, and the problem was resolved. I can only assume water pressure in the main pump cavity was 'escaping" past the diaphragm.

Hope this helps.

[IslandHopper]

Originally Posted by hd002e

Sorry if my post was not clear. This pump is the water pump for potable running water, not the bilge..

Is that what you mean?

[hd002e]

Originally Posted by wiekeith

I had a similar problem last year, which I appear to have resolved. On the rear of the unit is the switch mechanism that tuns the power on when the pressure drops, typically when a faucet is opened. The microswitch in the mechanism is operated by a small diaphragm. I removed it, cleaned it, put marine grease on the edges where it seals, and the problem was resolved. I can only assume water pressure in the main pump cavity was 'escaping" past the diaphragm.



Hope this helps.

Sounds like a plan! I did take it apart and attempt to clean but it already was clean so I dont think I contributed much. I do have some silicone grease sitting around from the shaft seal so I will do that! Thank you!!

[Scott Berg]

Originally Posted by hd002e

When I turn on the faucet, water comes out as usual. There is no one way valve in the entire system, I think it is pressure activated.

Makes sense about the rubber not sealing properly, I will look into a rebuild kit.

There are actually at least 2, maybe more, valves in the pump; as noted, they are probably not fully sealing

s

[rmez]

It's most likely air in the system. I've had this twice, once with a slightly loose fitting at the hose connection to the water tank, once due to a small crack in the housing of the small filter attached to my shurflo pump.
So first tighten all the connections (teflon tape or plumbers tape should be used). Then remove the filters (if any) as a test...replace as needed.

Of course before getting to this I had taken apart the pump, inspected and cleaned the diaphragm (its actually quick and easy to do this if you can access and remove the pump)

[canyonbat]

Rather than rebuilding it, I would just replace it and keep the old one as a spare. New ones are less than $100.

[meirriba]

Check the air pressure system of the reservoir by the pump. It may be leaking and the pump tries to build pressure again whenever it feels pressure loss.