Daikin water source heat pumps display fault codes that point directly to component failures such as sensor issues or flow problems. Owners access the complete master list through the unit control panel to diagnose without professional service calls initially.
The codes cover compressor operation, water flow rates, and temperature sensors across multiple Daikin series. Reference the table below to match displayed numbers with exact causes and required parts. This approach reduces downtime by identifying Daikin control board replacements or sensor swaps early.
WSHP Numeric Codes by Component Group
Daikin water source heat pumps log numeric codes that technicians cross reference against component groups. The system stores these values in nonvolatile memory for retrieval during service mode entry. Accurate interpretation prevents unnecessary part swaps and targets the root issue on the first attempt. Common codes appear across WSHP models in commercial and residential installations.
| Code | Component Affected | Typical Cause | Resolution Action |
|---|---|---|---|
| 01 | Compressor | Low refrigerant charge | Recharge system after leak test |
| 02 | Water flow switch | Blocked strainer | Clean strainer and verify flow |
| 03 | Leaving water sensor | Open circuit | Replace sensor and recalibrate |
| 04 | Entering water sensor | Short circuit | Replace sensor and check wiring |
| 05 | High pressure switch | Dirty condenser | Flush heat exchanger |
| 06 | Low pressure switch | Fan motor failure | Replace fan motor assembly |
| 07 | Freeze protection | Low water temperature | Increase flow rate setpoint |
| 08 | Control board | Voltage spike | Replace control board |
Daikin Water Source Common Service Codes
Three codes account for most service visits on Daikin water source units. Code 02 triggers when flow drops below 2.5 gallons per minute per ton. Code 05 activates from elevated head pressure caused by scale buildup inside the coaxial coil. Code 03 appears after sensor leads corrode in humid mechanical rooms. Technicians first confirm actual water flow with a portable meter before condemning the switch. Next they measure differential pressure across the heat exchanger to isolate restrictions. These steps isolate the problem without full system teardown.
Daikin Flow Switch Stock and Code Logs
Parts availability varies by region and model age. Stock Daikin flow switch and temperature sensor kits at branch locations to cover 70 percent of calls. Order Daikin control board assemblies with two day lead time for less common failures. Maintain a log of code frequency per site to predict seasonal demand spikes. Schedule filter changes quarterly to reduce flow related codes. Verify voltage stability at the disconnect before board replacement to avoid repeat failures.
Water Sensor Resistance Testing at Board
Sensor codes often cluster after power events or seasonal startup. Entering and leaving water sensors share the same harness routing, so one damaged wire affects both readings. Technicians test sensor resistance at the board connector before ordering replacements. Compare values against the Daikin resistance chart printed in the installation manual. Swap sensors temporarily to confirm the fault follows the part. This method rules out board channel failure in under ten minutes.
Daikin Compressor Pressure Amperage Checks
Compressor codes require pressure and amperage checks before any part removal. Measure suction and discharge pressures at the service ports while the unit runs. Compare readings to the Daikin charging curve for the current water temperatures. Low suction with normal amps points to a restricted metering device. High discharge with elevated amps indicates a failing compressor or noncondensables. Recover refrigerant and perform an acid test on the oil before condemning the compressor.
Reset Daikin Heat Pump System
Clear stored codes after each repair to verify the fix. Enter service mode by holding the up and down arrows for five seconds. Scroll to the reset function and confirm with the enter button. Cycle power to the unit and observe the display for fifteen minutes. Record any new codes that appear during this period. Retain the service log with date, code, and action taken for warranty claims.
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