Pressure Switch Maybe?

[Seth Clayton]

Hi all!

So we leave our house for 3 months in the winter each year. We return periodically for short visits, so we don't usually shut the water or heat off. We're on a well. At some point this winter, one of the faucet cartridges failed on an upstairs tub/shower and water leaked into the tub and down the drain (not sure how long this went on before it was found). I had a friend turn off the valve coming out of the pressure tank to the whole house to stop the leak until I came home to replace the faucet cartridge. I replaced the cartridge with no issues today, but when I opened the valve at the pressure tank, none of the faucets in the house would maintain pressure for more than a few seconds before the water slowed to a very weak stream. I suspected the pressure switch was bad at the pressure tank. I replaced it with a new 40/60 switch, and when I turned it back on it cut the pump off when the tank hit 40psi on a new pressure gauge that I installed along with the switch. I assumed that the "new" switch may have been defective, so I returned it for another. Installed that one, and I'm experiencing the same cutoff at 40psi as the first replacement. Any ideas what could be causing this? Is the well pump toast?

TIA

 

[Reach4]

It could be your new pressure gauge. Get another gauge with a garden hose thread and compare.

Also, have you set the air precharge on the pressure tank?

If you think the pressure gauge is OK, post a photo that includes the pressure switch and the piping between the pressure switch and the pressure tank.

 

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[Valveman]

Could just be 20/40 pressure switches that are not marked correctly. Tighten big adjustment screw about 6 full turns.

 

[LLigetfa]

when I turned it back on it cut the pump off when the tank hit 40psi on a new pressure gauge that I installed along with the switch.

As others say, it could be the gauge is reading wrong. It could also be that there is water hammer on start due to additional check valves in the system causing a strong pulse that the switch reacts to. It could also be where the switch is plumbed in relative to the tank.

Lastly, it could be that the diaphragm is stuck down to the bottom of the tank perhaps due to too much precharge or water trapped above it.

 

[Seth Clayton]

It could be your new pressure gauge. Get another gauge with a garden hose thread and compare.

Also, have you set the air precharge on the pressure tank?

If you think the pressure gauge is OK, post a photo that includes the pressure switch and the piping between the pressure switch and the pressure tank.

I think the pressure gauge is ok. The old pressure gauge was reading the same way with the old switch. I'll post a photo in a subsequent post. I precharged the tank to 38psi when it was empty via the valve stem on top.

Could just be 20/40 pressure switches that are not marked correctly. Tighten big adjustment screw about 6 full turns.

The label inside the cover of both replacement switches I tried were labeled 40/60, so hopefully there weren't 2 mispackaged switches. I played with the adjustment screw on the first replacement switch and couldn't get it to behave consistently or according to the standard 20psi differential. I could get the pump to run up to 60psi, but it wouldn't cut-in until the pressure dropped to below 30psi.

As others say, it could be the gauge is reading wrong. It could also be that there is water hammer on start due to additional check valves in the system causing a strong pulse that the switch reacts to. It could also be where the switch is plumbed in relative to the tank.

Lastly, it could be that the diaphragm is stuck down to the bottom of the tank perhaps due to too much precharge or water trapped above it.

While water hammer may be part of my problem, I don't think it's the primary issue. I can get the switch to turn the pump on and it'll run long enough that I would think the reaction to water hammer would be past quickly. How would I release a stuck diaphragm?

 

[Seth Clayton]

The moisture on the ground is from a leaky fitting on my drain hose and from some water that came out of the holes where the gauge and switch were replaced. Water supply from the well is coming in via the PVC pipe on right, while the feed to the house goes out copper pipe to the left.

 

[Reach4]

While water hammer may be part of my problem, I don't think it's the primary issue. I can get the switch to turn the pump on and it'll run long enough that I would think the reaction to water hammer would be past quickly. How would I release a stuck diaphragm?

If that amount of time is always over 10 seconds, I think we could eliminate a stuck diaphragm. How long does the pump run at minimum?

Your picture would seem to eliminate what we were thinking could be happening -- that the pressure switch was too separated from the pressure tank.

One obvious question is that at the time the photo above was taken, was the pump running? If not, why not? That would be a nice static situation. Water pressure at 20 PSI. 40/60 pressure switch not calling for water.

How does the air pressure compare to the water pressure gauge? Check at two different water pressure gauge readings. Make your maximum water pressure reading be included in one of the air-water pressure reading pairs. One thing this could uncover is a large difference in calibration of the air pressure gauge and the water pressure gauges. There may be something else that test would show... I don't know what.

 

[LLigetfa]

How would I release a stuck diaphragm?

... scratch that.

 

[Valveman]

Loosen the little adjustment screw all the way left so it isn't touching the spring. That should get you closer to the 20 PSI differential.