Installation and Operating Instructions
Gas burner WG20.../1-C ZM-LN (W-FM 25)
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83055116 • 1/2016-05
3 Technical description
3.3.2. Gas supply (cont.)
6
Low gas pressure switch
The low gas pressure switch monitors the gas supply pressure. With too low gas
pressure, the burner start will be prevented.
7
Additional low gas pressure switch
The additional low gas pressure switch monitors the gas pressure downstream of the
pressure regulator SKP25. For the burner start, the additional low gas pressure switch is
bridged by a timer for max. 5 sec. If the gas pressure switch is closed when the time has
elapsed, the V2 valve remains powered. If the output pressure drops below the setting
point, the pressure switch opens and cuts the power supply to the V2 valve actuator.
The V2 valve closes and the combustion manager initiates a lockout.
3.3.3 Electrical components
Combustion manager
The W-FM combustion manager is the main burner control unit. It controls the sequence
of burner operations, monitors the flame and communicates with all related components
in the system.
Operating interface
Via the operating interface, the operational related values and parameters of the com-
bustion manager can be displayed and changed. It is connected to the main unit via a
dedicated communication cable.
Burner motor
The burner motor drives the blower wheel. The combustion manager controls a motor
starter to run the burner motor.
Ignition device
The electronic ignition device generates spark at the electrodes to ignite the fuel-air mix-
ture during the ignition sequence.
Ionization electrode
The combustion manager monitors the flame signal via the ionization electrode. Should
the flame signal becomes too weak, a safety shutdown will be initiated.
