How to Adjust Your Well Pressure Switch

Understanding Pressure Settings

Cut-In vs Cut-Out

• Cut-in: Pressure when pump turns ON (low number)
• Cut-out: Pressure when pump turns OFF (high number)
• Differential: Gap between cut-in and cut-out

Common Settings

Why Adjust?

• Increase pressure (weak flow upstairs)
• Decrease pressure (protect old pipes)
• Match new pressure tank
• Reduce pump cycling

Safety First

Before Starting

1. Turn off pump at circuit breaker
2. Verify power is off (test with meter)
3. Note current pressure readings
4. Have flashlight available

When to Call Professional

• Not comfortable working with electricity
• Pump has other issues
• Switch looks damaged or burned
• Adjustments don't fix problem

Adjustment Steps

Tools Needed

• Flathead screwdriver or nut driver
• Pliers or adjustable wrench
• Flashlight
• Multimeter (to verify power off)

Locate the Adjustment Screws

Remove the switch cover. You'll see:

• Large nut/screw: Range spring - adjusts BOTH cut-in and cut-out
• Small nut/screw: Differential spring - adjusts gap between pressures

Adjusting Both Pressures (Large Nut)

• Clockwise: Increases both cut-in AND cut-out
• Counter-clockwise: Decreases both
• Each full turn ≈ 2-3 PSI change

Adjusting Differential Only (Small Nut)

• Clockwise: Increases cut-out only (wider gap)
• Counter-clockwise: Decreases cut-out (narrower gap)
• Usually leave this alone

Step-by-Step

1. Power OFF at breaker (VERIFY!)
2. Remove switch cover
3. Identify large and small nuts
4. Turn large nut 1/4 turn clockwise (to increase)
5. Replace cover
6. Restore power
7. Run water, observe pressure gauge
8. Note new cut-in and cut-out
9. Repeat if needed (small adjustments)

Limits

• Don't exceed pump's rated pressure
• Most residential pumps: max 60-80 PSI
• Check pump specs before going higher

Tank Air Pressure

Why It Matters

Pressure tank air charge must match switch settings for proper operation.

The Rule

Tank air pressure = Cut-in pressure minus 2 PSI

How to Check/Adjust Tank

1. Turn off pump
2. Drain tank (open faucet until water stops)
3. Check air pressure at tank valve (like tire valve)
4. Add or release air to match setting
5. Close faucet, restore power

If You Don't Adjust Tank

• Tank too low: rapid cycling, reduced water storage
• Tank too high: pump works harder, less drawdown

Troubleshooting

Pump Won't Turn Off

• Cut-out set higher than pump can achieve
• Lower the cut-out pressure
• Or there's a leak in system

Pump Cycles Too Often

• Waterlogged tank (needs air)
• Differential too narrow
• Leak in system

Low Pressure

• Increase cut-out setting
• But check pump can handle it
• May indicate pump issue, not switch

Burned or Pitted Contacts

• Switch needs replacement, not adjustment
• Sign of electrical issues
• Cost: $25-$75 for new switch

We service all major pump brands including Franklin Electric, Grundfos, Goulds (Xylem), and Sta-Rite (Pentair). Our trucks carry common parts and components for same-day repairs.

Frequently Asked Questions

How do I increase water pressure?

Turn large nut clockwise (power OFF first). Small adjustments—test between changes. Don't forget to adjust tank air pressure.

Which nut do I turn?

Large nut: raises/lowers both pressures together. Small nut: changes only the differential (usually leave alone).

What's the maximum pressure I should set?

Don't exceed your pump's rating (usually 60-80 PSI). High pressure can damage pipes and appliances.

Why does my pump cycle rapidly?

Usually waterlogged pressure tank (needs air charge). Can also be leak or narrow differential.

Can I damage my pump by adjusting the switch?

If you set cut-out too high, pump runs continuously trying to reach it. This causes overheating and damage.