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Building Technologies
Basic Documentation LMV5...
CC1P7550en
4 Burner control
22.05.2018
4.1.1.7 QRB
(for intermittent operation only)
No-load voltage at the QRB terminal
(X10-02 pin 1)
Approx. DC 8 V
Required detector current required
(with flame)
Min. DC 30 µA, display flame 35%
(at factory setting of
StandardFactor
)
parameter)
Permissible detector current during
extraneous light test
Max. DC 5 µA
Possible detector current
Max. DC 70 µA, display flame approx.
100%
(at factory setting of
StandardFactor
)
parameter)
Permissible length of QRB detector cable
(laid separately)
100 m (wire-wire 100 pF/m)
Β
Note!
A detector resistance value of RF <5 k
ς
is identified as a short-circuit and, in
operation, will lead to safety shutdown as if loss of flame had occurred.
Measurement of the voltage at terminal QRB during burner operation gives a clear
indication: If the voltage drops below 1 V, safety shutdown will probably be initiated.
For that reason, before using a highly sensitive photoresistive flame detector (QRB1B
or QRB3S), it should be checked whether such a detector is really required!
Increasing line capacitance between the QRB terminal and mains live «L» adversely
affects the sensitivity and increases the risk of damaged flame detectors due to mains
overvoltages.
Separate routing of detector cables as specified in Data Sheet 7714 must be
observed.
For more detailed information, refer to Data Sheet N7714.
Caution!
Flame detectors QRB must not be used when extraneous light suppression is
activated since detector tests are not made in that case (parameter
ExtranLightTest
= deactivated)!
Notice!
Observe the relevant standards and regulations (e.g. extra supervision of the
combustion chamber temperature)!
