How to Repair or Replace a Well Pump Pressure Switch

A well pump pressure switch is a critical component of a water well system. It controls when the well pump turns on and off in response to changes in pressure in the water line. Problems with the pressure switch can prevent the pump from turning on, cause it to cycle excessively, or not shut off when it should. Replacing or repairing a faulty pressure switch is usually a straightforward DIY project that can restore normal function.

What is a Well Pump Pressure Switch and How Does it Work?

A pressure switch is essentially an electric switch that is turned on or off by changes in water pressure. It consists of:

  • A diaphragm that detects line pressure changes
  • An electric switch connected to the diaphragm
  • Adjustment screws to set pressure cut-in and cut-out points
  • Electrical wires to connect the switch to the pump control box

The switch is installed in the water line leading out of the well pump. When a faucet is opened, pressure drops in the line. This actuates the diaphragm in the switch, closing the electric contacts and turning on the pump. Water is pumped into the system, increasing the pressure. At a preset cut-out pressure, the diaphragm is pushed back, opening the switch contacts and turning off the pump.

The pressure settings are typically around 30 psi for cut-in and 50 psi for cut-out. These allow the pump to maintain pressure in the system within a safe range. The differential between cut-in and cut-out pressures prevents the pump from rapidly cycling on and off.

Signs of Pressure Switch Problems

Some common signs that the pressure switch may be malfunctioning include:

  • Pump not turning on when water is used
  • Pump turning on and off frequently
  • Pump running non-stop with no water in use
  • Drop in water pressure
  • Air spurting from faucets
  • High pump cycling frequency

Any of these indicate the switch is not properly opening or closing in response to pressure changes. The specific symptoms point to whether the issue is with the cut-in or cut-out settings.

Pump Not Turning On

If no water comes out when a faucet is opened, the switch is likely failing to close and turn the pump on when it should. Causes include:

  • Faulty diaphragm
  • Contacts worn or stuck open
  • Cut-in pressure set too high
  • Power outage to switch

Pump Cycling Frequently

If the pump turns on and off rapidly with only brief periods of operation, the cut-in and cut-out pressures are too close together. This could happen because:

  • Cut-in setting is too high
  • Cut-out setting is too low
  • Bad diaphragm allowing pressure bleed-off

Pump Running Continuously

A pump that runs non-stop with no water being used indicates the switch is not opening at the cut-out pressure. This could be due to:

  • Cut-out setting too high
  • Faulty or stuck contacts
  • Ruptured diaphragm
  • Airlock preventing pump from pressurizing

Drop in Water Pressure

If water pressure is lower than normal throughout the system, the cut-in setting may be too low. The pump turns on at abnormally low pressures.

Air Spurting From Faucets

Air bubbles blowing out with water suggest the pump is unable to build normal pressure. The switch cut-out setting is likely set too high.

How to Test a Pressure Switch

Before replacing a questionable pressure switch, it’s a good idea to test it. This can confirm the switch is actually faulty before spending money on a new one.

You will need a multimeter capable of reading continuity. Test procedures include:

1. Check cut-in pressure setting

  • Turn off power to the pump
  • Open a faucet and bleed off line pressure
  • Connect multimeter leads across two switch wires
  • Slowly increase pressure on the switch using a bicycle pump or other pressure source. Note the pressure reading when the meter shows continuity (beep or zero resistance). This is the cut-in setting.

2. Check cut-out pressure setting

  • Start with no pressure on switch
  • Connect multimeter leads to switch wires
  • Multimeter should show continuity (closed circuit)
  • Gradually increase pressure on switch diaphragm
  • Note pressure reading when continuity stops. This is cut-out setting.

3. Check contact operation

  • Apply pressure below cut-in, multimeter should show closed switch
  • Apply pressure above cut-out, multimeter should show open switch
  • Tap/wiggle switch while watching multimeter. If readings flutter, contacts are faulty.

4. Listen for snap or click

  • Bleed off pressure below cut-in, then quickly increase it. A distinct snap or click should confirm closing electrical contacts.
  • Pressurize switch past cut-out then quickly release pressure. A click signals contacts opened.

If settings are way off, contacts malfunction, or no click is heard, the switch should be replaced.

How to Replace a Well Pump Pressure Switch

Replacing a pressure switch is a straightforward DIY project, especially if an exact replacement switch is used. Follow these steps:

1. Turn Off Power

Locate the circuit breaker or fuse powering the well pump and turn it off. Verify power is off at the pressure switch before proceeding.

2. Relieve Pressure

Open a faucet near the pressure tank. Once water stops flowing, the line pressure has been relieved.

3. Disconnect Wires

Label wires with tape so they can be reconnected correctly later. Then disconnect them from the switch terminals.

4. Unscrew Switch

The switch is threaded into a tee fitting. Use a pipe wrench to unscrew the switch counterclockwise.

5. Install New Switch

Wrap the threads of the new switch with Teflon tape. Hand tighten it into the tee, then use a pipe wrench to tighten another 1/4 to 1/2 turn. Do not overtighten.

6. Reconnect Wires

Refer to labels and reconnect the wires to the proper terminals. Double check connections are tight.

7. Restore Power and Pressure

Turn power back on at the circuit breaker. Turn on a faucet and let water run until all air is purged from lines and normal pressure restored before using water.

Test operation of the new switch by turning taps on and off and checking that pump cycles on and off appropriately. Use a pressure gauge to verify cut-in and cut-out settings are correct if pump operation seems abnormal. Most switches have adjustment screws to alter pressure settings if needed.

Troubleshooting Pressure Switch Replacement Issues

If the freshly installed pressure switch does not work properly, here are some steps to diagnose potential issues:

  • Use a multimeter to ensure power to the switch and pump control box when the pump should be on. Check for bad breakers or blown fuses.
  • Inspect wire connections. Look for loose wires, incorrect terminations, or shorts.
  • Check that supply line water pressure reaches typical cut-in pressure when faucet is opened. A problem with the well or piping could be preventing pressure drop.
  • Test cut-in and cut-out pressures with a gauge. Adjust settings if needed. Switch may have been disturbed during installation.
  • Listen for click when switch operates. If no click, the new switch is likely faulty and should be replaced with a quality unit.
  • Review pump and pressure tank sizing. An undersized pump can cause short cycling. Extensive cycling may call for a larger tank.
  • Bleed all air from system. Airlocks and bubbles can impede pump operation.

Thoroughly work through these checks until normal pressure switch operation is restored.

How to Repair a Pressure Switch

While a complete replacement is usually recommended for a malfunctioning pressure switch, repairs are possible in some cases. Attempting repair requires disassembling the switch to access internal parts. This should only be done by qualified technicians. Some possible repairs include:

Adjusting Cut-in and Cut-out Pressures

Many switches have adjustment screws that can alter the pressure settings if they become out of calibration. Turn screws clockwise to increase pressure. Make small adjustments and retest operation.

Cleaning Contacts

Buildup on the electrical contacts can prevent them from closing cleanly. Contacts can be accessed by disassembling the switch and cleaned with a solvent. Lightly sanding may help restore smooth operation.

Replacing Diaphragm

A ruptured or defective diaphragm will allow pressure to bleed off. The rubber diaphragm can sometimes be replaced, restoring a tight seal. Compatible replacements should be available from the switch manufacturer.

Replacing Seals and Gaskets

Leaking seals around the housing can also cause pressure leaks, cut-in/cut-out issues, and rapid cycling. Seals and o-rings can be replaced to stop leaks.

Contact Point Reconditioning

If pitted or worn, electrical contact points can be cleaned and polished to restore good connectivity. Inspect spring tension as well.

While possible, repairs require significant disassembly. A new switch is generally recommended overpotentially expensive repairs that may be temporary.

FAQs About Pressure Switch Repair and Replacement

What are typical pressure switch pressure settings?

Most residential systems have a cut-in pressure around 30 psi and cut-out around 50 psi. Well recovery rate determines optimal differential between settings.

How do I choose the right replacement switch?

Match pressure ratings and connection size. 30/50 psi and 1/2″ NPT threads are most common. Visually compare to old switch. Call tech support with model if unsure.

Is it safe to repair a pressure switch myself?

Basic replacement using proper precautions is safe for a DIYer. Attempted repairs inside the switch should be done by an experienced technician due to electrical and pressure hazards.

How can I adjust pressure settings on my switch?

Turn adjustment screws clockwise to increase pressure settings. Typically, a 14-turn adjustment screw changes pressure 2-3 psi. Adjust in small increments with testing.

What causes chattering or cycling too frequently?

If a pump cycles excessively, cut-in and cut-out pressures are likely set too close together. Widen the differential between settings to remedy.

Why does my pump run when no water is being used?

If a pump runs continuously with no fixtures open, the switch likely fails to open at the cut-out pressure due to a bad diaphragm, sticky contacts, or incorrect adjustment.

What happens if cut-in pressure is set too low?

If the pump turns on below the normal 30 psi cut-in, pressure tank waterlogging and system air problems can occur. Gradually increase setting.

Can I clean pressure switch contacts rather than replace?

Carefully cleaning pitted contacts with solvent and fine sandpaper may help if they are sticking and not closing cleanly.


A malfunctioning pressure switch is one of the most common causes of problems with well pumps. Thankfully, replacements are inexpensive and fairly straightforward for DIYers to swap. Saving a faulty switch by repairing the diaphragm, adjusting settings, or cleaning contacts is possible but can require technical skills. When in doubt, replacing the entire switch is the best solution to restore reliable water pressure.

How to Repair or Replace a Well Pump Pressure Switch

A properly functioning pressure switch is crucial for ensuring a well pump operates smoothly to deliver water on demand. This vital component senses drops in pressure when water is used and signals the pump to turn on and off at appropriate times. If the switch malfunctions, immediate repairs or replacement are needed to restore water supply and prevent damage. Fortunately, troubleshooting basic switch issues and installing a new one are fairly straightforward tasks most homeowners can handle. Here is a detailed guide on how to repair or replace a well pump pressure switch.

What Does a Well Pump Pressure Switch Do?

Before diving into troubleshooting issues and replacement, it’s helpful to understand what exactly the pressure switch does:

  • Mounted along the water line, the switch senses line pressure
  • When a faucet is opened, pressure drops below a preset “cut-in” point
  • The switch acts like a circuit closer, sending power to turn the pump on
  • The pump pressurizes the system until pressure reaches the “cut-out” setting
  • The switch then opens the circuit, cutting power to turn the pump off
  • This cycle repeats to maintain water pressure within a safe range

The cut-in and cut-out pressures are usually around 30 PSI and 50 PSI respectively. The differential prevents short cycling.

Signs of Pressure Switch Problems

Some obvious indicators that the pressure switch is malfunctioning include:

  • Pump not turning on when fixtures are opened
  • Pump turns on/off frequently (chattering)
  • Pump runs continuously, even with fixtures closed
  • Faucets sputter air
  • Drop in water pressure throughout home

Less noticeable symptoms are sudden spikes or drops in pressure, even if the pump seems to run normally. Any of these point to the need for pressure switch repairs or replacement.

Testing the Pressure Switch

Before replacing a possibly faulty switch, testing can confirm whether replacement is actually needed. Use these steps to test:

1. Check cut-in and cut-out pressures

Attach a pressure gauge and adjust pressure up and down on the switch, noting the readings when contacts open or close.

2. Inspect contacts

With power OFF, remove cover. Check contact condition and spring tension. Look for wear, pitting, corrosion, etc.

3. Listen for “click”

Place switch against ear while quickly increasing and decreasing pressure. A distinct click signals contacts are opening and closing cleanly.

4. Consider voltage & continuity tests

Use a multimeter to check for power and continuity. Consult a well professional for guidance on technical testing.

If adjustment is far off, contacts are damaged, or no click is heard, replacement is likely needed.

Replacing a Well Pump Pressure Switch

DIY replacement is straightforward. Follow these tips for smooth installation:

Choose an Identical Replacement

Match the pressure ratings, connection size, brand, and features of the old switch. This avoids compatibility issues.

Turn Off Power

Disconnect power at the fuse/breaker box before touching electrical connections.

Relieve Pressure

Open a faucet and drain all pressure from the lines before removing old switch.

Label Wires

Note wire locations to ensure proper reconnection.

Disconnect and Remove Old Switch

Unscrew switch counterclockwise using a pipe wrench if needed.

Install New Switch

Wrap threads with Teflon tape. Hand tighten, then use wrench to turn an additional quarter to half turn.

Reconnect Wires

Refer to labels. Tighten terminals securely.

Restore Power and Pressure

Turn power back on, let pump run until pressure gauge shows normal pressure.

Troubleshooting a Newly Installed Switch

If problems arise after installation, check:

  • Wiring connections
  • Piping for leaks
  • Cut-in and cut-out pressures
  • Water pressure reaching pump
  • Pump/tank sizing
  • Air in lines
  • Voltage to switch

Carefully work through checks until normal operation restored.

Repairing a Pressure Switch

Repairing a switch is possible but requires skill working with electrical and pressure components. Consider replacement instead, but these repairs can be attempted:

  • Cleaning or sanding pitted contacts
  • Replacing diaphragm
  • Replacing seals and gaskets
  • Adjusting pressure settings
  • Testing and replacing caps, springs, and points

Again, repairs should only be performed by experienced well professionals. Consult an expert for your specific switch.

Frequently Asked Questions

What are standard pressure settings?

30 PSI cut-in and 50 PSI cut-out are typical settings that maintain optimal household water pressure.

How do I know the right replacement part number?

The part number should be printed on the defective switch’s label. Confirm by comparing old and new visually.

Is it difficult to install a pressure switch myself?

Replacement is straightforward with proper power disconnect and pressure relief. Adjustments may be needed after install.

What if my pump runs when no water is being used?

Constant running with fixtures closed usually signals a problem with the cut-out pressure setting or diaphragm that prevents the switch from opening.

Why does my pump cycle on and off frequently?

Frequent short cycles usually mean cut-in and cut-out settings are too close. Adjust to widen the differential.

Can I repair the existing switch instead?

Technically yes, but repairs require expertise working with electrical contacts and pressure vessels under pressure. Replacement is strongly advised.


While a bit intimidating, diagnosing pressure switch problems and replacing faulty switches is quite manageable for most homeowners. The repair procedures require adeptness working with electrical and pressurized components, making replacement the best option in most cases. With proper testing, zeroing in on the cut-in and cut-out pressures, a new quality switch that replicates the old one can restore smooth water supply.

How to Repair or Replace a Well Pump Pressure Switch

A properly functioning pressure switch is critical for controlling well pump operation. This device senses drops in water pressure when fixtures are opened and signals the pump when to turn on and off. If pressure switch problems arise, a homeowner has two options – attempt repair or replace. This guide provides an overview of pressure switch operation, troubleshooting symptoms, steps for replacement, repairs to consider, and answers common questions on maintaining this vital system component.

What Does a Pressure Switch Do?

mounted along the water line leading to the home, the pressure switch serves to:

  • Monitor system pressure
  • Detect drops when water is used
  • Activate electrical contacts to turn pump on at low “cut-in” pressure
  • Turn pump off when pressure reaches higher “cut-out” setting
  • Repeat cycle to maintain