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5 Functional Description with Process Diagrams
5.2 Additional Burner Sequencer Functionality
5.2.1 Start Without Pre-Purge
NOTICE
The external signal for pre-purge suppression must be fail-safe.
5.2.1.1 Requirements
NOTICE
This function may only be activated if local regulations and the system configuration permit a
burner start without pre-purge or if sufficient pre-purge is ensured by other measures.
NOTICE
The function must be mapped.
5.2.1.2 Required Inputs/Outputs
The following digital inputs are required for the "pre-purge suppression" function:
•
Pre-purge suppression without testing for air pressure drop
If this input is mapped and activated, no pre-ventilation is carried out.
• Pre-purge suppression for gas according to EN676
If this input is mapped and activated, no pre-purge according to EN676 is carried out in
gas operation.
For a description of the digital inputs, see chapter 3.2 Digital Input/Output Functions
5.2.1.3 Required Parameters
This function does not require any special parameters.
5.2.1.4 Functional Description
Pre-purge suppression by an external signal
The pre-purge function can be skipped with the ’Pre-purge suppression’ signal. If the signal is
present before ’Burner start-up’, the actuators move directly to the ignition position.
The external light monitoring of the flame scanner is carried out prior to the start of the flame
detection (P 803).