Dixell/Copeland AL06

What does Dixell/Copeland AL06 mean?

The AL06 alarm on the Dixell IC100CX iChill controller is the evaporator water flow switch alarm. It activates when the flow switch digital input indicates inadequate or absent water flow through the evaporator circuit. The alarm is delayed by the time set in parameter AL04 from the start of the evaporator pump to prevent nuisance trips during start-up. The controller uses parameter CO11 to determine whether a water pump is configured.

Symptoms

• AL06 displayed on the IC100CX screen with flow icon lit.
• General alarm relay and buzzer activate.
• Compressors may be held off to protect the evaporator from freezing.
• Flow icon remains lit even after the condition clears if alarm is latched.

Common causes

• Evaporator water pump not running or tripped on overload.
• Flow switch failed or wired incorrectly — stuck open contact.
• Blocked strainer or filter on the evaporator water loop.
• Air trapped in the evaporator water circuit reducing effective flow.
• Water loop isolation valve partially or fully closed.
• AL06 delay parameter set too short for the system start-up flow development time.

Diagnostic steps

1. 01

   Confirm evaporator pump operation

   Check that the evaporator water pump is running and drawing correct current. Verify the pump starter or VFD has not tripped on overload and reset if necessary.

2. 02

   Inspect the flow switch

   Locate the evaporator water flow switch and verify the paddle or vane is unobstructed and moving freely. Use a multimeter to check continuity across the switch contacts with flow present.

3. 03

   Check for air in the circuit

   Vent air from the high points of the evaporator water loop using air vents or bleed valves. Air pockets reduce effective water velocity and can hold the flow switch open.

4. 04

   Inspect strainer and valves

   Check the evaporator circuit strainer/filter basket for blockage and clean if necessary. Confirm all isolation valves are fully open.

5. 05

   Reset the alarm and monitor flow

   After restoring flow, navigate to AlrM in the function menu, select AL06, and reset the alarm. Monitor the flow switch input status to confirm it remains closed with pump running.

When to call a professional

Call a licensed HVAC/R technician if the evaporator water pump requires mechanical repair or impeller replacement, if the flow switch requires replacement and its location involves draining pressurized piping, or if repeated AL06 alarms occur despite normal flow switch readings — indicating a controller input or wiring fault.