Few seconds of pulsing after taps turned off

[stuartwineberg]

When taps turned on water runs smoothly. When tap is then closed the pump pulses about 5 or 6 times then stops. It’s a newish jabsco pump that specifically says it doesn’t need an accumulator. No obvious leaks but if there were any I would expect the pump not to stop or to periodically run for a few seconds, none of that.

 

[Graham_Wright]

Sounds like air in the pipes.

 

[stuartwineberg]

Sounds like air in the pipes.

Hope you’re right. The system has been drained down

 

[LadyInBed]

It could be that the pump is just running until it reaches it's cutout pressure.
Is cutout pressure fixed or adjustable?

 

[ChromeDome]

Any hoses that can flex, holding more water when under pressure?

 

[Ammonite]

When taps turned on water runs smoothly. When tap is then closed the pump pulses about 5 or 6 times then stops. It’s a newish jabsco pump that specifically says it doesn’t need an accumulator. No obvious leaks but if there were any I would expect the pump not to stop or to periodically run for a few seconds, none of that.

Mine used to do this on my previous boat without an accumulator. It just takes a few pulses to reach the cut out pressure once you turn off the taps. Air in the system would extend the pulsing until it is expelled from the taps and if you have a leak the pump will pulse periodically with the taps closed.