Exceeding the nominal psi range of the pressure switch (and other questions)

[Tubby]

1) I have a 15-year old pressure switch rated for 30-50psi. Almost two years ago, I raised the setting to 40-60psi (after setting the tank air pressure to 38psi). It has performed since then with no problems. Is exceeding the nominal range indefinitely like this bad for the switch?

2) Should I be planning to replace the switch pretty soon anyway? There was no visible deterioration back when I made that adjustment.

3) I've noticed lately that the switch now cuts off a few psi above 60. I thought I had it right at 60 when I made that adjustment. Is this cause for concern, or should I just check the air pressure and readjust?

 

[Reach4]

1) No concerns having turned up the 30-50psi pressure switch to 40-60psi.

3) If you want to back it off, turn the nut on the big spring CCW. Each 3.5 turns reduces both the cut-in and cut-out pressures by about 20ps. So to drop by 2 psi, go 0.7 turn CCW.

The air precharge should be set to 2 psi below the cut-in. Air precharge is measured with the water pressure zero. You are supposed to check every year, but you can usually go more. Seems like a good time to check, while you are doing other stuff.

 

[Sponsor]

 

[Bannerman]

I've noticed lately that the switch now cuts off a few psi above 60.

Perhaps your pressure gauge is indicating not as accurately as it did previously.

You could obtain a pressure gauge equipped with a garden hose fitting to allow it's reading to be compared with the original gauge reading.

Alternately, because water within the pressure tank will cause the pre-charge air to be compressed to the same pressure as the water, use your tire pressure gauge to compare the pressure measured from the tank's Schrader valve while the tank is full and the pump is shut off.

 

[Valveman]

More likely it is just the gauge. If the gauge won't go to zero when the pump is off and the tank is empty, the gauge is tweaked.

 

[SuperGreg]

As far as I know, the same part is used whether you buy 30-50 or 40-60, just adjusted different. I personally had an old pressure switch rupture the diaphragm that seals off the water and had water spewing out of my well room (inside the house) and flooded the basement before we found out. From now on I will change them out before they get too old, but I also have chlorine injection that could have weakened the rubber.

 

[Reach4]

As far as I know, the same part is used whether you buy 30-50 or 40-60, just adjusted different.

I know they have some adjustment range, but I had suspected they had more than one spring strength to put them closer to the mid adjustment point for the labeled pressure. I don't know.

I personally had an old pressure switch rupture the diaphragm that seals off the water and had water spewing out of my well room (inside the house) and flooded the basement before we found out. From now on I will change them out before they get too old, but I also have chlorine injection that could have weakened the rubber.

Both points make sense. It seems that bleach will be bad for rubber life. Your pressure tank may deteriorate faster too. And replacing your pressure switch preemptively would be a good idea for you. Maybe others.

https://mykin.com/rubber-chemical-resistance-chart says that EPDM and Butyl would be better than nitrile for bleach. I think "bleach liquor" is what we would usually call bleach.