I moved into a house on a rural property in January, and we live off tank water and have a Grunfos PT18 pumping all our water into the house.The problem is, not all the time, but alot of the time my pump stays on after having a shower, the motor keeps running and restarting continuously as if it is desperately trying to pump more water through, until I go underneath my house and literally turn it off at the powerpoint, wait for a bit then turn it back on. I am scared if I leave the motor keep going like that it will burn my pump out. Does anyone have any suggestions on how I can fix this problem, or why it may be doing this, or is something causing it?Thankyou in advance, from someone who has next to no knowledge about pumps!!
Just adding a little more info to Corkeys list. Your foot valve could be stuck open and the water is draining back to the well. You will have to pull up the well line and replace the foot valve.
Is there a pressure tank on the system? If so, there is little to no air in the tank or the tank bladder if equipped has a hole in it. Try this. Turn off the power to the pump. Look for an air valve at the top of the tank and open it, there should be a slight hiss. While it is open, also open a tap in the house and drain off about 3 gallons of water. Now close everything and restart the pump. It should now run normal. All pressure systems require air on top of the water to operate, otherwise pump is waterlogged.
Sounds like it's waterlogged. That's what it's called when the water and the air in the resevoir tank mix, and the volume of air gets so small as to not be able to provide any decent compression with which to push water through the system. At that point, any time you open a fixture, the pressure drops enough to turn on the pump, and when you turn off the pump, if it's just right, it will turn off and then back on, then off, then on, back and forth till you shut it off and it can set and stabilize, till you need water again. The solution is to reintroduce a sizeable amount of air back into the top of the tank. If it's an older tank, without a bladder, (identified by the small bulge around the center of the tank and either a blue or rust color), then the best way is to simply drain the tank and restart the system. That way it will trap all the air in the top of the tank and you'll have enough pressurized air to push a gallon or two of water out, before the pump needs to kick on again. If it's the bladder type, with the bulge, then the bladder has blown and you're, in effect, working with a standard resevoir tank now, except that it will have an air valve in the top like a bicycle tire, so you can pressurize it with an air tank. If so, open some fixtures, start pressurizing the top of the tank and blow all the water out of the system. Once it's dry, put about 20 lbs. of pressure in the tank and start up the pump. You should be good to go.
