Water Pressure System

[frmreilly]

My water pressure pump comes on and off and builds up very little pressure. It happens with either tank, so I kn ow the problem is not related to the tank. When I turn both tanks off, the pump comes on full strength -- as soon as I open the water valve, it returns to quick burts of on and off. I actually changed out the pump and I still have the same problem. Any thoughts?

 

[Stu Jackson]

Have you cleaned the strainer (if you have one)? Are the screens in the faucets clean? Have you checked for any leaks in the piping downstream of the pump?

 

[rardiH36]

After never using the pressurized fresh water for two years since I bought my boat, I experienced the same situation as you described. The pump was new from the PO, but wasn't getting suction. Only burped out a bit of water now and then. When I removed the hoses from the tank-choice diverter valve I discovered water wasn't flowing naturally out from the tanks with gravity nor through the valve towards the pump. Gunk or something was had reduced the flow to almost nothing. I cleaned the diverter valve and ran a wire up the hoses to the tanks. The water pressure to the galley sink and head is now fine.

Looking through the inspection cover into the tanks, the water looked clean enough. I don't understand how the blockage occured.

 

[larryw]

How your pump runs depends on the type of freshwater system you have. If you have an acumulator tank, you pump will pressurize the system and you will be able to draw about a half-gallon or so, from any outlet, until the acumulator tank empties enough, drops pressure, and the pump come back on to recharge.
If you don't have an acumulator tank, your pump will work in spurts to keep a steady flow from the outlet and will shut off when the outlet is shut off. Most pumps have a pressure switch controlled by a screw to adjust pressure.

 

[Alan]

Curious about "..the pump comes on full strength". I can't figure how a pump could run at full strength with no water. Maybe you mean it is running full time? A cycling pump says to me that the water pressure builds and drops quickly. That sounds very much like a leak in the pressure side of the line. Closing the water supply to the pump would allow the pressure to drop to near zero(with a leak) which would run the pump full time.