Flame Detectors; Loss Of Flame - Siemens LMV37.4 Series Basic Documentation

Building Technologies

7.2 Flame detectors

For display of the flame on the AZL2, the following general conditions apply:

Display is subject to various component tolerances, which means that deviations of
10% can occur

Note that, for physical reasons, there is no linear relationship between flame display
and detector signal values
The LMV37.4 can be used with different types of flame detectors. For the correct use of
flame detectors, refer to chapter Sequence diagrams.
The flame detector used must be correctly parameterized.
Caution!
Only ionization probes are suited for continuous operation!
In the hardware of the LMV37.4, the flame signals are subdivided into 2 groups (group 0
covering the QRB and QRC, and group 1 covering ionization and the QRA). The flame
detector for gas is selected via parameter 221, that for oil via parameter 261.
No. Parameter
Gas: Active detector flame evaluation
221 0 = QRB / QRC
1 = ION / QRA
Oil: Active detector flame evaluation
261 0 = QRB / QRC
1 = ION / QRA

7.2.1 Loss of flame

In the event of loss of flame, the unit initiates safety shutdown, followed by a restart, if
required. A repetition counter can be used to select the number of flame losses after
which the unit shall initiate lockout (refer to chapter Repetition counter).
Error Diagnostic
code code
7 0
No. Parameter
Software drop out delay time of flame signal (100 ms)
186 Index 0 = QRB / QRC (0 = deactivated, >1 = activated)
Index 1 = ION / QRA (0 = deactivated, >3 = activated) (only 200 ms-steps)
Repetition limit no flame at the end of safety time
1 = no repetition
2...4 = 1...3 repetitions
194
Recharging time:
Entering into operation
Repetition limit value loss of flame
1 = no repetition
240 2 = 1 repetition
280
Recharging time:
After the Operation phase
Caution!
The response time of the flame detector leads to an extension of the second
safety time! This must be taken into consideration when designing the burner!
Basic documentation LMV37.4...
7 Basic unit LMV37.4
Meaning for the LMV37.4
Loss of flame
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CC1P7546en
17.12.2018