Dixell/Copeland AL22

What does Dixell/Copeland AL22 mean?

The AL22 alarm on the Dixell IC100CX iChill controller (firmware 1.8 GRU) is a general block alarm triggered when a digital input is activated continuously. The display shows 'bLOC' and the general alarm icon is lit. Manual reset is required — the alarm does not clear automatically even after the triggering digital input returns to its normal state. This represents a hard lockout of unit operation.

Symptoms

• AL22 and 'bLOC' displayed on the IC100CX FW1.8 GRU screen.
• General alarm icon lit; unit operation blocked.
• Alarm does not clear automatically when the digital input deactivates.
• Manual reset required from the function menu to resume operation.

Common causes

• External protection device continuously holding the general alarm digital input active.
• A persistent safety condition (e.g., high pressure, low flow, thermal fault) keeping the input closed.
• Wiring fault shorting the digital input terminal, simulating a continuous activation.
• AL23=1 configuration enabling the manual-block behavior for this alarm.

Diagnostic steps

1. 01

   Identify the continuously active digital input

   Access the IC100CX digital input status screen and identify which input is continuously active. Do not reset the alarm until the root cause is identified — a continuous safety activation means the protection is working.

2. 02

   Inspect the connected external device

   Locate the field device connected to the active digital input — such as a high-pressure switch, thermal protection relay, or flow switch. Determine whether it is correctly responding to an actual fault condition or has failed.

3. 03

   Check for wiring faults

   If the connected field device appears normal but the input reads continuously active, inspect the wiring for a short circuit between the input terminal and the common, which would simulate a continuously closed contact.

4. 04

   Resolve the triggering condition

   Correct the fault causing the external device to hold the digital input active. Do not bypass safety devices — if a high-pressure or thermal device has tripped, investigate and correct the cause before resetting.

5. 05

   Perform manual reset

   After the triggering condition is fully resolved and the digital input has returned to its normal state, navigate to AlrM on the IC100CX, select AL22, and press SET to execute the manual reset and restore unit operation.

When to call a professional

Always engage a licensed HVAC/R technician before resetting AL22 if the triggering digital input is connected to a refrigerant circuit safety device. A 'bLOC' lockout from a high-pressure or thermal protection indicates the system may not be safe to restart until a qualified technician performs a refrigerant circuit inspection.