Checking & Testing a Pressure Switch

How to check a pressure switch on a pump to see if replacement is needed

Preparation:
Safety First:

Turn Off Power: Ensure the power to the pump and pressure switch is turned off. This is crucial to avoid electrical hazards. You can do this by switching off the circuit breaker or removing the fuse that supplies power to the pump.
Use Personal Protective Equipment (PPE): Wear safety gloves and goggles.
Gather Tools and Equipment:

Multimeter (digital or analog)
Pressure gauge (if needed)
Screwdrivers (flathead and Phillips)
Wrenches (adjustable or specific size)
Insulation tape
Replacement pressure switch (if needed)
User manual for the pump and pressure switch
Step-by-Step Instructions:
1. Locate the Pressure Switch:
The pressure switch is typically mounted on the pump or close to the pressure tank.
It will usually have electrical connections and may have a cover or protective casing.
2. Inspect the Pressure Switch:
Visual Check: Look for any visible signs of damage or wear. Check for cracks, corrosion, or loose connections.
Wiring: Ensure the wires are securely connected. Look for any frayed or damaged wires.
3. Check the Pressure Settings:
User Manual: Refer to the pump’s user manual to find the correct pressure settings for the switch. You need to know the cut-in (turns on) and cut-out (turns off) pressure settings.
Adjustment: If the settings seem off, you may need to adjust them. Be cautious when making adjustments as incorrect settings can affect pump performance.
4. Test the Pressure Switch Continuity:
Set Multimeter: Set your multimeter to measure continuity or resistance (ohms).
Disconnect Wires: Carefully disconnect the wires from the pressure switch terminals.
Test Continuity:
For Normally Open (NO) Contacts: Place the multimeter probes on the terminals. The meter should show no continuity (infinite resistance) when the switch is not activated.
For Normally Closed (NC) Contacts: Place the probes on the terminals. The meter should show continuity (low resistance) when the switch is not activated.
Activate the Switch: Manually trigger the switch (if possible) or adjust the pressure settings to see if continuity changes as expected.
5. Check Pressure Readings:
Install Pressure Gauge: Attach a pressure gauge to the pump or the pressure tank’s gauge port.
Turn Power Back On: Restore power to the pump and observe the pressure gauge as the pump operates.
Monitor Pressure:
Compare the gauge readings with the pressure switch’s cut-in and cut-out settings.
The pump should turn on at the cut-in pressure and turn off at the cut-out pressure. If the switch doesn’t activate the pump within these pressures, it may be faulty.
6. Test Switch Operation:
Reconnect Wires: Ensure all wires are properly reconnected to the pressure switch.
Turn On Pump: With the pressure gauge installed and power restored, observe the pump’s operation.
Watch for Cycles: The pump should start and stop according to the pressure switch settings. If it doesn’t cycle properly, this indicates a problem.
7. Replace the Pressure Switch (if necessary):
Turn Off Power: Ensure the power is off before making any replacements.
Disconnect Pressure Switch: Remove the old pressure switch by unscrewing or disconnecting it.
Install New Switch: Attach the new pressure switch in place, reconnecting the wires as per the manufacturer’s instructions.
Adjust Settings: Set the new pressure switch to the correct cut-in and cut-out pressures according to the pump’s specifications.
Restore Power: Turn the power back on and test the new switch as described in the previous steps.
8. Final Checks:
Check for Leaks: Ensure there are no leaks around the pressure switch and connections.
Observe Performance: Let the pump run and observe its performance over a period to ensure that it’s operating correctly.
9. Documentation:
Record Findings: Document any issues found and actions taken. Keep a record of the pressure switch settings and any adjustments made.
By following these detailed steps, you should be able to determine whether your pump’s pressure switch needs to be repaired or replaced. If you're unsure about any part of the process or if the issue persists, consulting with a professional technician is recommended.