Basic Documentation

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Siemens Universal controllers RMU710B, RMU720B, RMU730B CE1P3150en
Building Technologies Support on errors and faults 03.10.2011
29.3 Troubleshooting
29.3.1 Fault indication
Fault status messages queued on the controller are indicated by the LED on the
fault button. This button allows you to acknowledge fault messages.
Meaning:
Fault status message Message ackn. LED status
Fault pending No Flashing
Fault pending Yes Lit
(also applies to messages
that must not be
acknowledged)
Fault no longer pending No Flashing
Fault no longer pending Yes Off
If a fault relay is also configured, the LED on the fault button always flashes when
the relay is energized.
If the LED on the fault button is lit and cannot be extinguished by mere
acknowledgement, a fault message is still pending. The LED extinguishes only
when no more faults are present.
29.3.2 Fault acknowledgement
No acknowledgement required
This applies to all fault messages that do not need to be acknowledged or reset.
If the outside temperature is not available, a fault message is generated. When the
outside temperature returns, the fault message automatically disappears and the
plant resumes normal operation.
Acknowledge
Applies to all fault messages that only need to be acknowledged. The fault must be
locked and reset externally.
When the fault message disappears (external reset), the plant resumes normal
operation even if the fault message was not acknowledged.
A frost protection unit requiring local reset is installed in the plant. The only purpose
of the fault indication is to ensure that the service staff notices the fault message.
Acknowledgement and reset
Applies to all fault messages that must be acknowledged and reset.
After acknowledgement, the fault message is maintained until the fault is no longer
present. Only then can the fault message be reset. After resetting, the LED in the
fault button extinguishes.
A fault s message from a filter must be acknowledged and reset. To prevent
regeneration of the fault message each time the plant is started, the message is
merely acknowledged. However, the fault message must be reset after the filters
are exchanged.
Fault messages from other controllers cannot be acknowledged on the controller.
Note
Example
Caution
Example
Example