Danfoss A45 Error Code

What does Danfoss A45 mean?

A45 indicates the Danfoss controller has stopped regulating because its main switch is set to off — the standby-mode message. On the EKC 313 this corresponds to the start/stop parameter r12 = off; on the ERC 21X it is shown as 'Standby Alarm' caused by the r12 Main switch. It is usually an intentional state rather than a hardware fault, but it means the controller is not cooling.

Symptoms

• Display alternates to show A45 (standby).
• Compressor and regulation outputs are switched off.
• Temperature in the cabinet or case is no longer controlled.
• Alarm relay may activate to flag that the unit is in standby.

Common causes

• Main switch parameter r12 has been set to off.
• A remote standby or stop signal has been applied via a digital input.
• The unit was deliberately placed in standby for service or cleaning.
• Start/stop input wiring is open, holding the controller stopped.

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Diagnostic steps

1. Confirm the standby state

   Press the top button to view A45 and confirm the controller is in standby rather than reporting a fault.

2. Check the main switch parameter

   Open the menu and read r12 (start/stop of regulation). Set r12 to On to resume regulation if standby was not intended.

3. Inspect any remote stop input

   If a digital input is configured for remote standby or stop, verify the external signal or switch is in the correct position.

4. Verify regulation restarts

   After setting r12 On, confirm A45 clears and the controller resumes cooling and temperature regulation.

When to call a professional

A45 is normally cleared by restarting regulation, so most operators can resolve it. Call a technician if the controller will not leave standby after r12 is set On, or if a remote stop signal cannot be located. They can trace the start/stop input wiring and confirm no protective interlock is holding the unit off. Persistent unexpected standby may indicate a wiring or control-network fault that needs trained diagnosis.