Loosing water pressure ? Pump runs , shuts, then repeats over & over

[al1026]

Since owing boat 2 years this on/off of the pump has plagued me. Low on the priority list I live with it, Now I want too correct .
​Boat is a 30 ft cruiser. I shut pump from control panel when done using water. Boat has a hot water tank not connected too engine . Gets hot off of dock side , holds temp
​No accumulator tank , for my own knowledge what does the accumulator tank do ?
​I did basic search , Two water lines, blue & red .
​Red is hot water tank all around too 3 sinks & shower. Blue is cold . One line goes into pump . I can not find were its loosing pressure causing pump too run shut then run a minute builds enough pressure , shuts, . This process would continue endlessly until I shut off at fuse panel
​I also checked pump under steeps . . Limited viewing anything . What method can I do too find were pressure leak is or is this normal since no accumulator tank No water leaking
As usual thanks

 

[Grub54891]

Usually the first place to look is the filter just before the pump, make sure it's clean. If you can't find any leaks it could be the pump itself, The tank holds a small volume of water so the pump don't run as often, and holds constant pressure.

 

[Faztbullet]

Could be bad pressure switch on pump.....

 

[alldodge]

No accumulator tank , for my own knowledge what does the accumulator tank do ?

An accumulator is a tank which contains a bladder and a spring. Water pushes in and fills tank compressing the spring. Pump shuts off and the spring pushes water out until the pump comes back on. In most such as yours, this would not be a benefit because you would need a different pump control.

It could be a bad switch as Fazt mentioned, but could also be the pump leaking internally. If it has an internal leak there is no external sign. Remove the line coming from the pump and cap closed. Turn pump on and see if it does the same thing

 

[Silvertip]

If you actually have a supply line pressure leak there would be water on the floor or a leaking/dripping fixture somewhere. But a system without a pressure tank (an accumulator) must cycle on and off. Opening a fixture tells the pump to run which forces water to the fixture. Turning off the fixture causes pressure in the system to rise until the pressure switch shuts the pump off. Without an accumulator, the cycling would be rather rapid and depend on whether the fixture is fully open or just part way open. A bad check valve in the pump as All Dodge says, could create an internal pump leak with no visible sign of leakage.