Wolf CGB-2-24 - Gas;Air Mixture Control and Calibration; Gas-Adaptive Combustion Control Principle; Calibration Process

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6. Electronicgas/airmixture
Gas-adaptivecombustionaircontrol
Principle:
The relationship between the actual ionisation current and
excess air is used for combustion control.
The system carries out a continuous set/actual comparison
for the ionisation current.
The control unit adjusts the gas throughput via the electronic
gas valve to match the actual ionisation current to the set value.
Set values for the ionisation current for every output value are
stored in the system.
Calibration:
For all gases, the ionisation current is at
its maximum when Lambda λ (air ratio) = 1
● Thesystemcalibratesautomaticallybybrieyshiftingto
Lambda 1.
● BrieyincreasedCOemissions
Whendoesthesystemcalibrate?
1. Each time the mains supply is switched on.
2. Cyclically after a certain number of burner starts and a
certain burner runtime.
3. After certain faults such as "Flame failure during operation".
CO emissions may be increased during cali-
bration.
Please
note
Fig: Ionisation current control diagram
λ=1,35λ=1
Luftzahl [λ]
Ionisationsstrom [Io]
Io
soll
Regelbereich
Io
max
Airratio[λ]
Ionisationcurrent[Io]
Control range
SET