Re: Piston Water Pump
Posted by More on May 29, 2001 at 01:53:07:
In response to Re: Piston Water Pump
To give you instructions on what to do to set the pressure, one requires an idea of how the system is arranged. Is the piston water pump connected to and powered by an electric motor which shuts itself down? If so, does the electric motor receive its power through a water pressure sensitive relay? If so does the water pressure sensitive relay also receive an air pressure signal from an expansion tank? If so, does the air pressure gauge on the expansion tank read 20 pounds per square inch or better? If not, then the air expansion tank has developed a leak in the diaphragm and has become waterlogged. The piston pump pressurises water against the expansion tank which contains an internal elastic diaphragm, which in turn expands against the tank and squeezes air (or sometimes nitrogen) against the gauge. When adequate pressure is reached, the air pressure switch opens, and upon opening, disconnects electrical contact for the pump motor. If the diaphragm leaks, adequate air pressure can't get squeezed, and pressure won't build, so the switch won't disconnect power to the motor, so it runs (electrically) till it overheats.The electric motor has a protective reset switch inside it to keep it from starting fires, and when it cools, it can restart, since the diaphragm hasn't disconnected it's power yet, and the cycle continues.

You need to ascertain that the diaphragm is good or bad. Assume its bad.There is a serial number and a plate with the manufacturer's name on the expansion tank somewhere. Call a company called Grainger's (or a local well driller or the tank manufacturer) for a price for a new tank and diaphragm and air/water pressure switch. Replace what you have, replace the wires in the same position they are removed from, and the pump will work fine.BE Careful of the electrical.....if you aren't sure, get help, or e-mail me for help.

: I have an ols piston water pump at my camp. It works really well except the pressure isn't set correctly. It comes on all the time and the water comes to fast. Also with it running this way as it recycles it shuts itself off uuntil it cools down. it wasn't always like this. I would like to adjust it myself. Can you give me some instructions on what to do? Thanks Jean Dobson

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