Resetting a Daikin high pressure switch starts with power isolation followed by a targeted reset sequence on the control board. This approach clears the lockout and restores compressor operation in most residential and light commercial units.
Technicians and experienced owners follow the same steps to avoid repeated trips and unnecessary service calls. The process also includes basic inspections that prevent the switch from activating again due to simple obstructions or low airflow conditions.
Acquire Daikin Pressure Reset Equipment
Homeowners need a few specific items before starting any work on the Daikin outdoor unit. These tools allow safe access to the high pressure switch and control board without risking damage to wiring or components. Proper preparation also reduces the chance of misreading fault codes during the reset. Gathering everything in advance keeps the job moving once power is off.
| Item | Purpose | Quantity |
|---|---|---|
| Multimeter | Check voltage and continuity at switch terminals | 1 |
| Insulated screwdriver set | Remove access panels and terminal screws | 1 set |
| Daikin service manual | Locate exact reset button and wiring diagram | 1 |
| Safety gloves | Protect hands during panel removal | 1 pair |
Secure Work Area Before Reset
Safety checks come first when working on any Daikin system that has tripped on high pressure. The outdoor unit must be completely isolated from power to prevent accidental startup during inspection. Owners should also clear the area around the unit of debris and confirm the indoor thermostat is set to off. These steps protect both the technician and the equipment from further faults.
Locate the main disconnect switch for the outdoor unit. Verify zero voltage at the contactor with the multimeter. Remove the service panel screws and set them aside in a magnetic tray.
Execute Pressure Switch Reset Procedure
The actual reset occurs at the printed circuit board inside the Daikin outdoor unit. After power isolation, the high pressure switch can be manually cleared through a dedicated button or by cycling the board. Technicians watch for the fault code to disappear on the display before restoring power. This sequence must be completed in order to avoid triggering a new lockout.
Press and hold the reset button on the PCB for five seconds. Observe the LED indicators until the high pressure code clears.
Reinstall the service panel and restore power at the disconnect. Run a short test cycle to confirm the compressor starts without immediate shutdown.
Daikin High Pressure Switch Error Codes
Error codes on Daikin units often point directly to the high pressure switch or related sensors. Reading the code before reset helps confirm whether the switch itself failed or if an external issue caused the trip. Common codes include E1 and E3 series that relate to pressure protection. Matching the displayed code to the service manual prevents unnecessary part replacement.
Owners should note the exact code shown on the indoor remote or outdoor board. Cross-reference that code with the manual section on pressure switch faults. Record any secondary codes that appear after the first reset attempt.
Validate Reset Through Performance Checks
After the reset, the system must be monitored during a full cooling or heating cycle. Measure suction and discharge pressures to ensure they stay within normal operating ranges for the specific Daikin model. Listen for unusual compressor sounds that could indicate the switch is about to trip again. These checks confirm the reset solved the root issue rather than masking it.
Attach gauges to the service ports and record readings at startup. Compare values against the Daikin specifications listed in the manual. Monitor the unit for fifteen minutes without fault recurrence.
Install Replacement Pressure Switch Unit
When the switch fails to hold after multiple resets, replacement becomes necessary. The new switch must match the original pressure rating and electrical connections used on the Daikin model. Installation requires brazing or flare connections depending on the unit design. Always evacuate the system properly before opening the refrigerant circuit.
Remove the old switch by loosening the flare nut or cutting the capillary tube. Thread the new switch into place and tighten to the specified torque.
Reconnect the electrical leads and secure the wiring harness. Perform a leak check with nitrogen before recharging.
Confirm Full System Functionality Post Reset
Final verification ensures the Daikin unit operates without returning to high pressure lockout. Run the system through multiple cycles while watching pressures and temperatures at both indoor and outdoor coils. Document the successful reset in the service log for future reference. This step closes the job and reduces callbacks.
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