Chiller flow switch
Part: model-specific water flow switch
Check first on low pressure, freeze protection, and low evaporator leaving-water-temperature faults.
$45-$180
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Daikin Applied Chiller Fault Codes — Quick Reference
Daikin Applied chillers (WMC water-cooled scroll, AGZ air-cooled, ALZ air-cooled scroll, and centrifugal units) use the MicroTech III or MicroTech 4 controller to display alarms and shutdowns.
| Fault Code | Meaning | Quick Fix |
|---|---|---|
| Low Pressure Cutout | Suction pressure too low | Check refrigerant charge and evaporator flow |
| High Pressure Cutout | Discharge pressure too high | Check condenser flow/fan and refrigerant |
| Low Evaporator LWT | Leaving water temp too low | Check flow rate and load |
| High Motor Temp | Compressor motor temperature high | Check voltage, load, and cooling |
| Freeze Protection | Evaporator temperature near freeze | Check flow, setpoints, and antifreeze |
| Comm Fault | Controller communication loss | Check BACnet/Modbus wiring |
| Compressor Fault | Compressor protection tripped | Check motor protection and contactor |
| Low Refrigerant | Refrigerant pressure low on both sides | Inspect for leaks, check charge |
Most Common Faults
Low Pressure Cutout
Low suction pressure is the most frequent chiller alarm. On water-cooled units, check the chilled water flow rate through the evaporator — low flow causes the refrigerant to get too cold. Also check refrigerant charge. On air-cooled units, verify ambient temperature is within the unit’s operating range.
High Pressure Cutout
Discharge pressure is too high. On air-cooled chillers, check: condenser coil cleanliness, fan operation (all fans running), and ambient temperature. On water-cooled units, check condenser water flow rate and entering condenser water temperature.
Freeze Protection
The evaporator approach temperature has reached the freeze protection threshold. Check for: low chilled water flow (pump failure, valve closed), low load causing low flow, or incorrect setpoints. Do not defeat freeze protection — a frozen evaporator is a major repair.
MicroTech III Navigation
- HOME → ALARMS to view active alarms
- ALARM HISTORY to view past events with timestamp and conditions
- SETPOINTS to verify operating limits
- UNIT STATUS to view live sensor readings
Parts Often Needed
| Part | Notes |
|---|---|
| Refrigerant charge | Common after leaks |
| Condenser fan motor | Replace on high pressure faults |
| Flow switch | Inspect on low pressure and freeze faults |
| Pressure transducer | Check on unexplained pressure readings |
Technician Tips
Daikin Applied chiller faults usually come from chilled-water flow, condenser airflow or water flow, refrigerant pressure, compressor protection, sensor readings, or MicroTech controller inputs. Match the alarm to the exact chiller model and circuit before replacing sensors or boards.
DIY vs Pro: Verifying strainers, pump operation, setpoints, and obvious loose controller wiring is a reasonable first pass for trained maintenance staff. Refrigerant work, compressor diagnostics, high-voltage motor testing, and controller configuration need a qualified chiller technician.
Need Replacement Parts?
Use the fault-matched Daikin Applied chiller parts above first, then confirm the model number, voltage, and sensor or board family before ordering.
Jump to Fix
- Low pressure → Check chilled water flow → Check refrigerant charge → Inspect evaporator
- High pressure → Check condenser coil → Verify all fans running → Check condenser water
- Freeze protection → Confirm flow rate → Check pump and valves → Verify setpoints
When to Call a Pro
Daikin Applied service providers handle refrigerant work, compressor replacement, and control system configuration. Contact Daikin Applied service at 1-877-554-4834.