EVCO AL16

What does EVCO AL16 mean?

AL16 on the Evco SAVE AHU controller (144SAVEU0E01) is a real-time clock (RTC) fault alarm. The controller has detected that its onboard clock has stopped, lost its settings, or that the backup battery powering the RTC has discharged. When AL16 activates, all time-dependent control logic — including scheduled start/stop, night setback, weekly programmes, and time-stamped HACCP logging — is inhibited until the clock is restored and the alarm is manually reset by an operator.

Symptoms

• AL16 displayed on the SAVE AHU controller.
• Scheduled start/stop and time-band programmes are no longer executing.
• Night setback and energy-saving time schedules are inactive.
• HACCP or event log entries show incorrect or zero timestamps.
• Alarm requires manual operator reset — it does not self-clear when power is restored.

Common causes

• Onboard RTC backup battery has discharged — common after 5–7 years of service.
• Extended mains power outage has depleted the RTC battery faster than normal.
• RTC clock module on the controller PCB has failed.
• Controller firmware update or cold-start reset the clock registers to a default invalid state.
• Severe supply voltage disturbance corrupted the clock registers.

Diagnostic steps

1. 01

   Access the clock settings menu and re-enter the date and time

   Navigate to the controller's configuration or clock menu and enter the correct current date and time. On SAVE AHU controllers this is typically found under the setup or scheduler section of the interface.

2. 02

   Confirm AL16 clears after clock is set

   After saving the correct time and date, perform the manual reset of AL16 from the alarm menu. If the alarm immediately returns after being cleared, the battery or RTC module is faulty — re-entering the time will not hold.

3. 03

   Inspect and replace the RTC backup battery

   Power down the controller and locate the coin-cell backup battery on the PCB (typically a CR2032 or equivalent). Measure voltage — replace if below 2.5 V. Use the exact voltage and chemistry specified in the SAVE controller documentation.

4. 04

   Restore time-dependent programmes and verify scheduling

   After resetting the clock and clearing AL16, check that all weekly programmes, night setback settings, and scheduled start/stop events are still correctly configured. A battery failure may have cleared these settings.

5. 05

   Document the battery replacement in the maintenance log

   Record the date of RTC battery replacement. Schedule the next replacement in 5–7 years. Repeat AL16 events without power outages indicate the new battery was not correctly seated or is the wrong type.

When to call a professional

Engage a licensed HVAC controls technician if AL16 recurs within hours of clock reset and battery replacement, which indicates a failed RTC module requiring board-level repair or controller replacement. In applications where HACCP timestamp accuracy is required for regulatory compliance — food processing, pharmaceuticals, healthcare — a technician should assess whether the gap in timestamped records during the AL16 period requires documentation and review by a food safety or quality officer.