I have a shallow well, single drop jet pump for my house. It recently cavitated destroying the PVC suction line going into the pump housing and the switch was melted internally. Obviously the pump ran continuously and overheated. Prior to this occurrence, I had been having a consistent problem with switches not kicking on when reaching cut in pressure of 20psi. I have the system set for 20/40. Intermitently, as the pressure would start to drop it would continue dropping below 20psi until it hit zero and the pump would just never kick on. I wouldn't know this occurred until turning on a faucet on and I would have no water. Walk out to the garage, tap the switch, it instantly kicks the pump on, pressure builds until the switch reaches cut out, pump turns off, pressure is at 40psi and all is well. Excuse the punn. Normally after that, it would work fine for apprx another weeks or so. Once it starts, it happens more and more frequently. It has happened with several switches now. Based on the fact that the pressure instantly builds back up, I'm assuming that I never loose my prime on the pump. I verified that my tank pressure is right on the money, so no indication of a problem there. I have absolutely no idea why or what the real cause is. Find hard to believe I would have the same consistent problem switch after switch? Please help.

"and the switch was melted internally."

That's kind of interesting. Sounds as though something is drawing too much current. Your switch should be able to stay in the "on" position for hours at a time and not overheat. That could also explain the other switches failing. Does it ever throw a breaker? Have you replaced the pump that overheated, or does it continue to operate OK?

There is a small pipe leading to the switch. Sometimes they clog. Check the small pipe.

Never had an issue with the pump tripping the breaker. Even during this last issue when the switch melted, it did not trip the breaker. I will check into the current draw issue. This house was built in 1970 and unfortunitely for me, has aluminum wiring. I have not installed a new outlet where the pump plugs in, as I have done throughout the rest of the house. Upon moving in I cut and stripped fresh all the aluminum wiring and installed brand new CO/LAR outlets and switches but have not done so for the well pump which runs off 110VAC right there at the wall behind the pump. I will have to try that. Definitely would think that it would trip the breaker or at least make the breaker warm if I had a current issue within the circuit? I have been told that the hole going to the diaphram in the switch can clog with sediment but I have cleaned everything and/or replaced several times when having this issue and still ended up having the problem. I would guess a sediment clog could be a regular occurrence, especially since the water quality is not that good and it's filtered but only prior to going into the house, but I would think that it would take longer than a month or so for sediment to build up to negatively affect anything. If sediment in the switch is the issue what is the fix, since it would seem to be a regular reoccuring problem?

I doubt that sediment is the problem, but I would think you could simply put the switch on a 90 degree elbow so that the little pipe going to the switch goes up, not sideways. The sediment would then tend to settle in the pipe. But I doubt it is the problem. I would be very visible when you pull the switch.

Is the wire going to the switch aluminum?

What size is the breaker?

The wiring to the wall outlet for the pump is AL. The wire from the switch is copper a regular cord with a three prong plung on the end. Right now I have the 90 elbow on the bottom of the switch and the tube does run down hill from the pump.

To clarify, the press tube leave the pump a 90 elbow on the top of the housing then runs down hill to a 90 on the bottom of the switch, so the water does have to go up in to hit the diaphram but sediment could accumulate at the elbow on the switch.

I doubt that sediment is the problem

I think I disagree. If sediment is blocking the switch to keep it from coming on it is probably also blocking it from shutting off. I don't think the aluminum wiring is a factor here. If the switch fails to open the points when reaching maximum pressure, the motor will keep running and as the pressures builds the resistance of the water pressure will increase the load on the motor until the motor overheats.

You said you have cleaned the tubing at the switch diaphragm. Did you insure the tubing is clear all the way to the pump. If this is an ongoing problem you may want to consider relocating the switch. It can be located any where along the piping. To do this you would remove the switch and plug the hole, put a tee in the piping, install the proper size bushing and install the switch. Rewire to the motor. If you came out of the tee vertically and installed a length of piping, then bushed down for the switch that should also reduce sediment. The water in the length of pipe should stay in the pipe even as pressure drops. Using this same, small volume of water repeatedly, to control the switch would greatly reduce the amount of sediment reaching the switch.

Right now my switch is mounted to the side of the motor and 1/4"OD pressure tube runs up hill where it 90s out of the pump. So you recommend that I install a T fitting to the 3/4" pipe that leaves the pump and mount the swtch on it directly to it via the port for the diaphram on the bottom of the switch thus elliminating the 1/4" pressure tube?

HK, having read your post, it seems you might be right. I looked at this, "I have been told that the hole going to the diaphragm in the switch can clog with sediment but I have cleaned everything and/or replaced several times when having this issue and still ended up having the problem. " That statement would tend to lead me away from sediment, since clearing away the sediment should do away, at least for a while, with the problem. However, if you have a noticeable and continuing accumulation of sediment, then that could be the problem.

Only thng that I found resemblng sediment upon remvl of the swtch I would pat the btm of the switch, elbow rmvd, with my hand and I get what lks like microscopic coffee grounds. Very minimal at best. Nothing drastic like a clogged tube or fitting.