- AL012 alarm is shown on the chiller's display, indicating "No Flow" in Pump 1's circuit. The chiller likely shut down shortly after startup or won't start the cooling process.
- You may notice no water moving through the chiller's pipes for circuit 1 – for example, the pump is running but there is no flow, or the pump might have turned off due to the alarm.
- If the chiller has a flow indicator or sight glass, it will show stagnant fluid. Additionally, other related alarms like low pressure or freeze protection might accompany this if flow was lost while running.
Closed Valve or Blockage
The most common cause is a closed valve in the circuit or a clogged filter that restricts water flow. If someone accidentally left an isolation valve shut, or the strainer is dirty, the flow switch will trip.
Pump Not Running or Failed
Pump 1 might not be operational – it could be off due to an electrical issue (blown fuse, overload trip) or mechanical failure, so it's not pushing water.
Faulty Flow Switch
Less commonly, the flow switch sensor itself could be malfunctioning or stuck, falsely reporting no flow even if water is moving.
Inspect the Cooling Loop Valves
Verify that all valves on Pump 1's loop are fully open. Check the supply and return lines for any closed hand valves or automatic valves that should be open during operation.
Check and Clean the Filter/Strainer
A blocked filter will reduce flow. If accessible, inspect the chiller's water strainer or filter for debris. Clean out any sludge or blockages to restore proper flow.
Ensure the Pump is Powered
Listen or check if Pump 1 is running. If it's not running at all, its breaker or overload might have tripped. You may need to reset the pump's overload (follow steps similar to AL008 if applicable) or replace a blown fuse. Only do this if qualified to work on the electrical panel.
Reset the Alarm
Once corrective steps are taken (valves open, filter clear, pump running), reset the AL012 alarm on the control panel. Hold the alarm reset button for about 5 seconds and release it to clear the error.
Observe Chiller Operation
After reset, monitor the flow indicator or check piping to confirm that water is circulating properly. The alarm should not reappear if flow is restored. Also, ensure the pump has stable current draw (no further overloads).
Professional Help Required:
- If AL012 persists even after opening valves and cleaning filters (and verifying the pump is running)
- If the pump overload keeps tripping when you start it
- If you suspect the flow switch is faulty (showing no flow despite good circulation)
- Anytime you are not comfortable performing the troubleshooting steps
There may be a more complex issue such as airlock in the system or a failed pump impeller. A technician can perform deeper diagnosis, check pump performance, and test the flow switch integrity.