[RDallett]

My fresh water pump keeps coming on every few minutes. No water is leaking into the bilge. The water pressure at the faucet does not appear to drop. When I switch to my backup water pump it has the same result. I have searched everywhere for leaking water and find nothing. Coul it be an air leak on the intake side?

 

[tdw]

My fresh water pump keeps coming on every few minutes. No water is leaking into the bilge. The water pressure at the faucet does not appear to drop. When I switch to my backup water pump it has the same result. I have searched everywhere for leaking water and find nothing. Coul it be an air leak on the intake side?

What is probably happening is that the return cut off valve is failing. I cannot speak for your exact pump but inside any pump is a valve that opens when you ask for water and then closes to prevent water in the pipes from draining back down into the tank. Because the pump is self priming it will respond by pumping water back up which then drains away again and so the circle of life continues.

You'll see no leaking water as it is simply draining back into the tank.

Solution is a rebuild of the pump which from my experience is no big deal. You can usually buy a kit.

 

[RDallett]

Thanks. I have a set of valves that allow me to switch from one pump to a backup pump. The cycling continues when I switch from one pump to the other. I thin it unlikely that they both failed in the same way at the same time. Any thoughts?

 

[Capt Len]

Unwritten law of boating. Backup stuff fails too. So do switches and valves. A larger accumulator tank would at least allow a longer time between cycling. (if the backup pump sees constant pressure but doesn't do anything about it ,it won't take long to harden up and lose function when asked to seal.)

 

[PorFin]

If you already have an accumulator tank, it may need to be purged. Every time my fresh water pump cycles frequently, this has been the cause.

Turn off the power to the pump, then open the closest tap down stream. Hook a bicycle pump (or a low pressure tire inflation pump) up to the Schraeder valve on top of the tank, and pump air into it. If you get any additional water coming from the tap, then keep pumping until the water stops running, and you get up to the rated tank pressure. Unhook the air pump and replace the dust cap. Turn on your water pressure pump and see if that's solved your problem.

 

[RDallett]

Thanks for your suggestion. Actually, I have 2 accumulators tanks in a series. Do you think I should follow your procedure for each separately or just the one closest to the pumps or something else?

 

[Delta-T]

Yes, you can have an air leak on the intake side that will cause the pump the cycle. I've been there, it was the connection at the pump.