Well pressure switch adjustment: adjust it, or replace it?

What the two numbers mean

Every well pressure switch is set to a cut-in pressure (pump turns on) and a cut-out pressure (pump turns off) — commonly 20/40, 30/50, or 40/60 psi on residential systems. The full breakdown of standard settings and tank precharge values is on the Well Pump home page.

Signs adjustment is the right move

• You're intentionally changing ranges — for example moving from a factory 40/60 down to 30/50 for gentler older plumbing.
• The switch cycles cleanly and consistently, just at pressures you want to shift up or down.
• The cover, nuts, and contacts look clean with no rust, pitting, or scale buildup.

If that's your situation, the full procedure — including turn counts and the adjustment order — is on our step-by-step adjustment guide.

Signs to stop adjusting and replace instead

• Cut-in is stuck and won't move even after the range nut is turned. A documented case on terrylove.com involved a 30/50 switch stuck at 34 psi cut-in no matter how the large nut was adjusted — the diagnosis was sediment or mineral buildup under the diaphragm, not a setting problem.
• The differential won't stay put or keeps drifting between cycles — a sign of worn or pitted contacts rather than a nut that needs turning.
• The switch is old. Square D's own Pumptrol 9013FSG-series switches are rated for roughly 300,000 mechanical cycles; a switch pushing 10-15 years of daily well use is closer to end of life than to a quick fix.
• Visible corrosion or burnt contacts inside the cover — replace and don't attempt further adjustment.

Precharge still matters either way

Whether you adjust or replace, reset the tank's air precharge to 2 psi below your final cut-in pressure — checked with the tank fully drained and the pump off. That's the manufacturer rule from the Amtrol Well-X-Trol installation manual (see Sources), and skipping it is a common reason a "fixed" switch still seems to short-cycle. If cycling continues after the precharge is correct, the cause is more often the tank than the switch — see our short-cycling guide.