Jabsco Water Pump Cycling Occasionally

[lawrence_craig]

Hi there,

I have an issue where my Jabsco Water Pump Par Max 2 cycles occasionally (once every 2-3 hours). It would suggest a leak somewhere but there's none to be found. I have taken the pump apart and cleaned the pressure switch mechanism to make sure nothing was restricting it. Is there anything else I should look at or try?

Many thanks.

[sailingharry]

I have that issue right now. I am betting that the check valves are either hard or have a bit of crud under them and water is slowly leaking back. While it's annoying when I hear the pump run, the fact that I'm not losing water means I am not losing sleep over it.

[Tetepare]

Is there water in the bilge?

I’m no proponent of Occams Razor but with cycling water pumps, it’s usually a tiny leak.

[lawrence_craig]

No water. And I have followed all water lines through the boat and can't find anything at any joins or outlets.

[Sailmonkey]

Originally Posted by sailingharry

I have that issue right now. I am betting that the check valves are either hard or have a bit of crud under them and water is slowly leaking back. While it's annoying when I hear the pump run, the fact that I'm not losing water means I am not losing sleep over it.

This is it……a slow leak back to the tank

[lawrence_craig]

Can you elaborate on this? Is this a check valve (one way valve) before or after the pump? My current water piping ends at the furthest point and doesn't route back to the tank.

[sailingharry]

It's not really an identifiable check valve, it is integral to the pump. Usually it is a three chamber device, and each chamber has a little rubber disc in it that is the check valve.

I have had some success in the past with dismantling the pump, cleaning and massaging all the parts (yes, they do like a good back rub) and reassembling. All the gaskets are rubber, so it can be disassembled and reassembled with no parts required.

[lawrence_craig]

ahhhh, ok, makes sense, I know the disks you're talking about. I'll pull the pump and give them a look. Thanks

[Stewie12]

The disks might have calcium build up on them which could be the cause of your problem, if so, a soak in vinegar will get that off without harming the disc.

[clakiep]

Not wanting to be a retrograd oldie : on the boat I sailed most - Brazil, Greece and back from 1973 to 1075 - we had to little pumps to be switched on and off. One for the bathroom and one for the kitchen. Plus one pump in reserve. Never needed it. Never any problem with switches or pressure switches. System KISS (keep it simple stupid).

Capt. Claus ocean tramp of the eighties

[Scrimshaw4]

Had the same problem. Internal scale buildup allowed backflow. Ordered repair kit but discovered it was incorrect for the age of my pump. Contacted their customer support and since the pump couldn't be repaired with the kit due to internal changes they replaced my pump.

[LouK]

Does your system have an acccumulator or pressure storage device? Two boats avoid found this device would leak pressure & cause the pump to run, never leaked water, just air.

[rondelais]

After you have had the cycling over several hours of not using any water, do you get any sputter-sputter from a faucet? You may have an air leak somewhere. Your may not see a water leak, especially on the supply side of the pump. I had the cycling problem until I took all lines apart, including he ones from the tanks, and redid the connections carefully, with teflon tape and sometimes pipe dope. Of course, I may have fixed an “invisible” leak in the process.

[Moana Bella]

Ours does that too.
But rather than start pulling things apart, I just convinced myself its caused by evaporation in the hot water tank, and the accumulator re-pressurising the system with the small intake of additional water.
Please - nobody say anything. Nothing is leaking. I'm not fond of plumbing jobs - and blissful ignorance is still bliss on a boat - right?

[rondelais]

You have a good point about the water heater. Mine is 6 gallons, and they tell me that when water is heated from 60 to 140 F the water expands by about 12 ounces So,, after the engine heats it up, the dishes are done, and we settle in for the night, the cooling could cause enough contraction to need more water. Mine doesn’t do that because I have an accumulator on both the cold and hot paths, as recommended by Raritan to avoid overpressure when heating. Could that be it?