The pre-alarms appear as messages in the message line and must be acknowledged by the operator. They do however not cause a safety shut-off.

The firing plant is shut down immediately, for example, if the boiler pressure or the boiler temperature exceeds the critical limit. To ensure that the operator is informed in a timely manner that the pressure or temperature is rising or falling to a critical value, a pre-alarm is automatically triggered when these values are reached.

The boiler pressure and boiler temperature are monitored continuously in order to determine whether a pre-alarm has to be triggered. This takes place either internally via the actual value of the load controller, or via an externally generated digital input signal. You can use the following parameters to define whether the values will be returned via a digital input signal.