New fresh water pump

[George and Dragon]

Our Jabsco water pump died on Thursday, fortunately just after we got back to the marina.

At first I could hear the pump trying to turn so I took it out and had a look at the inlet strainer which looked a bit grubby but not blocked. Gave it a clean anyway in a jug of clean water and got a few bits of crud off but nothing major so decided to reassemble but now the pump wasn't showing any sign of running.

Decided to bite the bullet and get a replacement but 11 litres per minute has magically gone from 2.9 US gpm to 3 gpm. Cutout pressure the same, but I clearly need to make some adjustments as the accumulator doesn't appear to be working correctly - as soon as a tap is opened the pump starts to run and there's a kind of stutter when it shuts off.

I'm wondering how to get back to normal operation - in my mind the pump shouldn't start to run until some water has been drawn and the pressure in the accumulator drops; the stutter doesn't seem right either.

[Tony Brooks]

Sounds as if you may have introduced some air into the system - the stutter may be air exiting the tap.

 

Pressurise the accumulator to about half the pump cut OUT pressure or the cut in pressure. @Tracy D'arth has a way of setting the pressure without a gauge.

[George and Dragon]

Thanks Tony

 

If it's air in the system I'm hoping this just means it will sort itself out over time...

Will leave it for now. It seems to be slightly better already (or is this wishful thinking?)

Edited May 27, 2023 by George and Dragon
added a bit

[Jen-in-Wellies]

2 hours ago, George and Dragon said:

Thanks Tony

 

If it's air in the system I'm hoping this just means it will sort itself out over time...

Will leave it for now. It seems to be slightly better already (or is this wishful thinking?)

If it's that, it will almost certainly sort itself out.

[blackrose]

I set my accumulator to a few psi below the pumps cut -in pressure with the water pump switched off and a couple of taps open so that the system isn't pressurised.

[Tony Brooks]

38 minutes ago, blackrose said:

I set my accumulator to a few psi below the pumps cut -in pressure with the water pump switched off and a couple of taps open so that the system isn't pressurised.

 

As long as the accumulator pressure is around the cut in pressure, it won't make a discernable difference.

[George and Dragon]

Spoke to the Xylem (Jabsco's parent company) rep at Crick this afternoon. He suggests the old pump may not have been delivering full pressure and I should check the accumulator. Which I will do when I have time to dismantle half the back of the boat (yes, it's tucked away in a very inaccessible place). 

[George and Dragon]

The problem I'm having is that I can easily get the accumulator up to about 20psi but can't get the pump off without losing it all. Any tips?

[Tracy D'arth]

4 minutes ago, George and Dragon said:

The problem I'm having is that I can easily get the accumulator up to about 20psi but can't get the pump off without losing it all. Any tips?

There is something wrong with the connector on your pump or the Schrader valve in the accumulator is not screwed home.

[ditchcrawler]

6 minutes ago, George and Dragon said:

The problem I'm having is that I can easily get the accumulator up to about 20psi but can't get the pump off without losing it all. Any tips?

Are you following the correct procedure? Turn off the water pump, turn on and leave on the taps. When the water stops running connect an air pump to the Schroeder valve on the end of the accumulator. Pump up to the required pressure. Remove air pump and replace cap, close taps and switch on water pump

[George and Dragon]

It doesn't seem to matter losing a small amount of pressure when I reflate a car tyre but that's a much bigger volume even though the pressure is similar.

 

2 minutes ago, ditchcrawler said:

Are you following the correct procedure? Turn off the water pump, turn on and leave on the taps. When the water stops running connect an air pump to the Schroeder valve on the end of the accumulator. Pump up to the required pressure. Remove air pump and replace cap, close taps and switch on water pump

That'll be it. Close the taps after pressurising. Thank you.

Work in progress - I got the pressure way too high to start with but now down to about 15 psi. The pump is 25 psi. Pump still runs when I open the tap and pulses when I close it...