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STZM@ ed 05/04 ZEUS Maior @
Technical Documentation
Technical Documentation
Flue pressure switch contact control
e control unit checks switching of the flue pressure switch contact as a result of the fan working (normally open contact NO)
Flue pressure switch contact control
e control unit checks the correct position of the flue pressure switch (normally closed contact NC)
ZEUS Maior @ operating sequence.
Central heating phase Domestic hot water phase
Power on
Main switch on Winter
Powering the adjustment board and CAR (if mounted)
When the main switch’s contacts close (Winter position) the modulation
board and CAR (if mounted) are powered and operation in the central
heating mode is enabled.
Powering the pump and 3-way diverter valve
e modulation board powers the boiler circulator and the electric 3-way
diverter valve that is moved into the d.h.w. position
Power on
Main switch on Summer or Winter
Domestic hot water operation request
e temperature of the water in the storage tank is below the set tem-
perature
Closing the system pressure switch micro
When the pressure in the primary circuit is higher than the minimum cutoff value, it causes the system pressure switch contact to close
Powering the fan
e board powers the fan
Powering the ignition control unit
e modulation board powers the ignition control unit
Powering the gas valve coils
With the enable of the overtemperature safety thermostat, the control unit powers the gas valve coils and sends the soft ignition signal to the modulation
board
Burner ignition (soft ignition)
e boards sends the soft ignition current to the modulating coil
Flame detection
By means of the ionisation electrode the control unit detects burner ignition and sends the burner ignition signal to the modulation board
Powering the adjustment board and CAR (if mounted)
When the main switch’s contacts close (Summer position) the modulation
board and CAR (if mounted) are powered and operation in the domestic
hot water mode is enabled.
Closing the room thermostat switch/CAR operating request
e request of the room thermostat or CAR (if mounted) detects the
conditions that require operation in the central heating mode.
Powering the circulator and 3-way valve
e modulation board powers the boiler circulator and the electric 3-way
diverter valve that is moved into the central heating position.
Powering the ignition electrodes
e control unit powers the ignition electrodes
Boiler working
e burner works at a power that varies according to the type of request, to the adjustments/settings made and to the temperatures detected by the NTC
probes
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