Fresh water pump kept cycling, simple fix...

[Mischief Managed]

My 35 psi fresh water pump died a few hours into the 2022 season. My spare was a 70 psi unit I got on Amazon that I thought would make for nicer showers (it does). I installed the spare and the extra pressure immediately overwhelmed quite a few "Flair-It" brand polybutylene couplers and Tees in my fresh water system, causing many leaks. I fixed them all but the pump would still cycle once every 45ish minutes with no water use. I could not find any leaks anywhere and decided that the back flow check valve in the pump must have a slow leak which would just send water back to the tank, not into the bilge.



Rather than take the pump apart and see if I could fix it, I bought a nifty little 1/2" "i Flow H20" check valve and installed it on the pump inlet hose, which took about 2 minutes. It works great and stopped the cycling. Seems like a decent redundancy upgrade that I can leave in place forever.

 

[rslifkin]

That's a good fix. I haven't had that issue with a fresh water pump, but if I leave it on, my washdown pump will cycle like that due to water leaking back through the pump.

 

[Comodave]

We had that issue with our last motorhome. Pump would cycle periodically and no leaks. Backflow through the pump was the problem.

 

[smitty477]

We had one that did that as well - the culprit ended up being a sliver of plastic that was wedged in the backflow on the pump. Easily fixed.

70 psi on domestic water system is not preferred for many reasons - some of which include: ice makers, fittings, backflow valves, water heaters, etc.
Rather spent some time making sure that the dock side pressure was 'reduced' to 50# or less before entering the boat.

 

[Mac2]

We had one that did that as well - the culprit ended up being a sliver of plastic that was wedged in the backflow on the pump. Easily fixed.

70 psi on domestic water system is not preferred for many reasons - some of which include: ice makers, fittings, backflow valves, water heaters, etc.
Rather spent some time making sure that the dock side pressure 'reduced' to 50# or less before entering the boat.

Totally agree! I had the same thought process as the OP and adjusted my pump up to 60 PSI. This caused numerous leaks throughout my boat over a couple of months. Extremely difficult to locate as they would only leak at the higher pressure and would stop as it dropped.

Highly recommend you turn off the water pump when you leave the boat if you don't already do this. My neighbor sprung a leak under the kitchen sink when he was gone and ruined his saloon floor.

 

[Russell Clifton]

I had a similar problem a few years ago. Thought for sure there was a leak somewhere but could not track it down. Then one day, for some reason, I got my stethoscope out and started listening to the various parts. Finally could hear the water running through a check valve. Replaced valve, problem fixed.

 

[Simi 60]

Have a similar thing on ours
Designed for fuel but.....

$6.70 for 2 delivered.
https://www.ebay.com.au/itm/2pack-O...d-10e5-4064-99b2-3677ab2185de&redirect=mobile

 

[River Song]

Check valve fixed it!

I had a similar problem a few years ago. Thought for sure there was a leak somewhere but could not track it down. Then one day, for some reason, I got my stethoscope out and started listening to the various parts. Finally could hear the water running through a check valve. Replaced valve, problem fixed.

We had problems with rapid cycling of our fresh water pump. After reading this we decided to try replacing our check valve. It has been two days and no more rapid cycling. Thanks for the great tip!

 

[River Song]

My 35 psi fresh water pump died a few hours into the 2022 season. My spare was a 70 psi unit I got on Amazon that I thought would make for nicer showers (it does). I installed the spare and the extra pressure immediately overwhelmed quite a few "Flair-It" brand polybutylene couplers and Tees in my fresh water system, causing many leaks. I fixed them all but the pump would still cycle once every 45ish minutes with no water use. I could not find any leaks anywhere and decided that the back flow check valve in the pump must have a slow leak which would just send water back to the tank, not into the bilge.



Rather than take the pump apart and see if I could fix it, I bought a nifty little 1/2" "i Flow H20" check valve and installed it on the pump inlet hose, which took about 2 minutes. It works great and stopped the cycling. Seems like a decent redundancy upgrade that I can leave in place forever.

Mischief Managed, Thank you for posting the size and name of the check valve you used. It enabled us to place a quick Amazon order for the check valve, and complete the least expensive repair we have ever made on our boat.