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well/pressure switch

The water supply to my wife's house (and my new one) is a well with an air bladder tank. She has replaced the pressure switch 3 times in about a year.
Even though the plumber has adjusted the tank air pressure and installed a new switch, the pump won't turn on and we are left waterless on occasion. After a short while (usually a couple of hours) the pump then works fine.
Any ideas as to why the pump/switch is so temperamental?

Re: well/pressure switch

The thing you need to determine is if the contacts in the switch are closed (making contact) when the pump is not running but should be. In most pressure switches, the cover is removable and the contacts are visible. Be careful you don't touch the live electrical parts of the switch.

Is the pump an above-ground or submersible pump?

The pressure switch has a rubber diaphragm between the inlet and the mechanical linkage. If you've got a lot of sediment or scale in your water, sometimes that can build up between the base and diaphragm and prevent operation. You could carefully disassemble the switch and see if this is the case -- also check the tiny hole in the base that lets the water into the diaphragm chamber. If you poke something into the hole to clear it out, be careful because you could rupture the diaphragm.

If you find out there's junk getting in there, make sure the switch is mounted so that the pipe leading to it is vertical with the switch on top. Lengthening this pipe may help.

Re: well/pressure switch

Thanks for your reply. I will check out what you recomended and let you know what I find out.
The pump is above ground. Also, I don't know if this makes a difference, but read somewhere that the distance from the pump to the house may be an issue. The pump is approximately 200 feet from the house.

Re: well/pressure switch

Unlikely that the distance to the house can be an issue, or even the distance from the pump to the tank. What CAN be an issue is the distance between the tank and the pressure switch -- this should be no more than about 10 feet, and there should be no check valves between the tank and switch. If the switch is mounted on the pump, then the tank should be no more than 10 feet of pipe away.

(10 feet is just a guess. I saw one case where the tank was too far away. What would happen is that when the pump shut off, the inertia of the water in the pipe kept it flowing -- think water hammer -- and that would cause the pressure at the switch to momentarily drop below the cut-in point, so the pump would turn on and then the pressure would jump above the cut-out point and the whole cycle would repeat.)

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