Daikin Chiller Error Code 99

Full Diagnosis

Reports a low water (brine) level condition detected in the thermal storage tank, typically by a float switch or level sensor feeding the chiller's thermal storage logic, and the control disables ice-storage charge/discharge cycling until an adequate level is confirmed. Unlike 98, which trips on brine pump overcurrent — an electrical or mechanical pump fault — 99 is strictly a level-detection fault and does not by itself indicate the pump has failed. Confirm the actual tank level before assuming a sensor problem, since a genuinely low tank will trip this code even with fully functional wiring and float switch.

All Recorded Causes

Actual low brine or water level in the thermal storage tank. Brine leak or loss from the tank or piping. Stuck or fouled float switch. Disconnected or damaged float switch wiring. Defective level sensor. Incomplete tank fill after service work. Blocked make-up water line to the tank.

Verify Before Replacing Parts

1. Confirm the exact Daikin model family and chiller context before acting on a generic code description.
2. Verify airflow first, then confirm operating pressures and temperature relationship before adjusting charge, since actual low brine or water level in the thermal storage tank.
3. Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm brine leak or loss from the tank or piping.
4. After the correction, run the system long enough to confirm the chiller fault does not return under normal load.