Fresh water pump cycling every minute or so

[Cardo]

Our reasonably old Jabsco fresh water pump has suddenly started cycling for a second or so every minute or so. It has always cycled for a second or so every hour or two since we've had the boat (2.5 years), but today, after I had my shower, it's suddenly cycling about every minute.

I'm aware the pump is old, and this particular model hasn't been on sale for over 10 years. I was advised in a previous thread that the pressure sensor could well be on its way out due to its age.

Question is: Could these symptoms relate to the pump being on its way out? Is the pressure sensor failing, or the non-return valve within the pump gone?

I don't mind replacing the pump if it's likely to be the fault, but if the above symptoms don't tally with the pump being old, then I'll need to find out what else might be wrong.

I've checked the pipes and can't find any leaks. I've been having issues with our hot water tank, but I don't think that's directly related to our new problem.

 

[VicS]

If you are absolutely sure there are no leaks. No leaks in hidden places like ....... ??????? ....calorifier/ hot water system?

Its the pump valves letting the pressure escape back though the pump

Jabscoshop website should have diagrams and parts lists

Might respond to a good clean but if old probably due for new valve kit.

Fit filter on inlet if not already fitted

 

[PuffTheMagicDragon]

Mine cycles like that when I don't close the tap firmly enough.

 

[NickTrevethan]

As vics said check for leaks. Our pressure relief valve on the calorifier got tired and dumped water over the side.

If no leaks swap the pump.

 

[No Regrets]

It may have an adjustment screw under a cover!?

Mine is adjustable, from very gentle, to a pipe blowing amount!!

I turned it up once, and the bilge filled up with lovely clean water. LOL

soon turned it down, but hey, showers were just like at home!

 

[NickTrevethan]

Same for us after I switched the the 2.6 bar pump for a 4 bar. That killed of the prv entirely!

 

[NormanS]

All it needs is a tiny spec of "dirt" under a valve in the pump. Generally not difficult to strip, and clean, or to replace valves, if required.

 

[Birdseye]

Our reasonably old Jabsco fresh water pump has suddenly started cycling for a second or so every minute or so. It has always cycled for a second or so every hour or two since we've had the boat (2.5 years), but today, after I had my shower, it's suddenly cycling about every minute.

I'm aware the pump is old, and this particular model hasn't been on sale for over 10 years. I was advised in a previous thread that the pressure sensor could well be on its way out due to its age.

Question is: Could these symptoms relate to the pump being on its way out? Is the pressure sensor failing, or the non-return valve within the pump gone?

I don't mind replacing the pump if it's likely to be the fault, but if the above symptoms don't tally with the pump being old, then I'll need to find out what else might be wrong.

I've checked the pipes and can't find any leaks. I've been having issues with our hot water tank, but I don't think that's directly related to our new problem.

Much more likely its muck in one of the valves - a hair maybe. Tap water isnt dirt free. So take the pump off the motor and carefully clean it out before contemplating anything in the way of parts or replacement.

 

[LadyInBed]

Loosing pressure somewhere in the system, do you have a pressure guage in the system that you can monitor?

 

[vyv_cox]

I'm with Birdseye and NormanS. We have had this problem several times in the past, due to a small piece of some solid being drawn into the pump and sitting beneath one of the valves. In our case we have had small particles of silicone sealant from the tank inspection plate and flakes of copper corrosion product from the inlet pipes. Since fitting a suction strainer all this stuff is trapped before entering the pump. Strip down the hydraulic head of the pump and clean the valve seats. I have had several pumps that were well over ten years old on which the valves were still fully functional, so there is every chance that a cleanup is all it needs.

 

[VicS]

I'm with Birdseye and NormanS.

Who have both repeated what I said right at the beginning in #2.

 

[vyv_cox]

Who have both repeated what I said right at the beginning in #2.

Sorry VicS, I'm with you as well! :encouragement: if a thing is worth saying it is worth saying twice, or even four times.

 

[Cardo]

I'm with Birdseye and NormanS. We have had this problem several times in the past, due to a small piece of some solid being drawn into the pump and sitting beneath one of the valves. In our case we have had small particles of silicone sealant from the tank inspection plate and flakes of copper corrosion product from the inlet pipes. Since fitting a suction strainer all this stuff is trapped before entering the pump. Strip down the hydraulic head of the pump and clean the valve seats. I have had several pumps that were well over ten years old on which the valves were still fully functional, so there is every chance that a cleanup is all it needs.

Job done, thanks guys. Turned out to be a small bit of crud stuck behind the valves. I actually managed to make it worse to begin with, so the pump would just run without causing suction! But after reopening it and thoroughly cleaning out the crud behind the rubber valves, we're back in business. No longer seems to cycle every hour, either.

The old pump still has some life in her, yet!