Dixell/Copeland AL09

What does Dixell/Copeland AL09 mean?

On the Dixell IC100CX iChill controller, AL09 sets the condensing temperature or pressure high alarm setpoint for the condenser analogue input probe. When the condenser probe value rises above AL09, the controller signals the high condenser alarm after the AL10 count threshold is checked and the alarm delay expires. This protects the refrigerant circuit from excessively high condensing pressure.

Symptoms

• High condenser temperature or pressure alarm activates when probe exceeds AL09 setpoint.
• Alarm relay activates; general alarm icon illuminates on the display.
• Compressor may stop depending on system configuration and number of events reaching the AL10 count.
• Repeated high condenser alarms escalate to manual reset lockout after AL10 events per hour.

Common causes

• Condenser coil fouled with dirt or scale, reducing heat transfer and elevating condensing temperature.
• Condenser fan failure or reduced airflow through the coil.
• High ambient temperature exceeding system design limits.
• Overcharged refrigerant system pushing condensing pressure above normal range.
• Non-condensable gases (air) in the refrigerant circuit raising condensing pressure.

Diagnostic steps

1. 01

   Check condenser probe reading against AL09 setpoint

   View the condenser probe value on the IC100CX display. Confirm the AL09 setpoint in the AL sub-menu is appropriate for the refrigerant and system design condensing temperature range.

2. 02

   Inspect condenser coil and fans

   Check the condenser coil for dirt, scale, or debris. Confirm all condenser fans are operational and running at correct speed. Clean the coil if fouled.

3. 03

   Check ambient conditions

   Measure the ambient temperature at the condenser. High ambient combined with a dirty coil is the most common cause of high condensing temperature in air-cooled condensers.

4. 04

   Verify refrigerant charge

   Connect manifold gauges and check subcooling. Excessive subcooling indicates overcharge. Non-condensables show as elevated head pressure with higher than expected subcooling.

5. 05

   Review AL10 maximum alarms per hour

   AL10 sets the maximum number of high condenser alarm events per hour before manual reset is required. If AL09 is tripping repeatedly, AL10 will eventually latch the unit out. Resolve the root cause before this point.

When to call a professional

If high condensing conditions persist after coil cleaning and fan verification, a licensed refrigeration technician must assess refrigerant charge, presence of non-condensable gases, and system capacity versus load. Refrigerant work and non-condensable removal require proper EPA Section 608 certification and appropriate recovery equipment.