Technical data
Technical documentation 
Technical documentation
STZS ed. 06/03
29
ZEUS SUPERIOR
ZEUS Superior OPERATION SEQUENCE 
Central-heating mode 
D.h.w. mode 
POWER SUPPLY    POWER SUPPLY 
Main switch in WINTER position 
Main switch in SUMMER or WINTER position 
⇓ 
⇓ 
MODULATION CARD AND C.A.R. (remote 
control) POWER SUPPLY 
MODULATION CARD AND C.A.R. (remote 
control) POWER SUPPLY 
When the main switch contacts close (WINTER position) 
the modulation board and C.A.R. (if fitted) are powered and 
operation in central-heating mode is enabled 
When the main switch contacts close (SUMMER position) 
the modulation board and C.A.R. (if fitted) are powered and 
operation in d.h.w. is enabled 
⇓ 
⇓ 
CLOSING OF ROOM THERMOSTAT SWITCH 
/ CAR OPERATION REQUEST 
DOMESTIC HOT WATER OPERATION 
REQUEST 
Room thermo. or CAR (if fitted) request detects conditions 
that require operation in central-heating phase 
Storage tank water temperature below that set 
⇓ 
⇓ 
PUMP AND 3-WAY VALVE POWER SUPPLY 
PUMP AND 3-WAY VALVE POWER SUPPLY 
The modulation board powers the circulator and the electric 
3-way valve 
The valve is moved to central-heating position 
The modulation board powers the circulator and the electric 
3-way valve. 
The valve is moved to d.h.w. position 
⇓ 
⇓ 
  CLOSING OF PUMP PRESSURE MICROSWITCH   
The circulation of water inside the primary circuit causes the closing of the pump pressure 
switch 
⇓ 
  FLUE PRESSURE SWITCH CONTACT CONTROL   
The card checks the correct position of the flue pressure switch (contact NC normally closed) 
⇓ 
FAN POWER SUPPLY 
The modulation board powers the fan   
⇓ 
FLUE PRESSURE SWITCH CONTACT CONTROL 
The modulation board checks the deviation of the flue pressure switch contact following fan 
operation (contact NO normally open) 
⇓ 
  IGNITION CONTROL UNIT POWER SUPPLY   
The modulation board controls the ignition control unit   
⇓ 
IGNITION ELECTRODES POWER SUPPLY 
The ignition unit powers the ignition electrodes   
⇓ 
  GAS VALVE POWER SUPPLY   
 With the consensus of the overheating thermostat, the ignition unit powers the gas valve coils.   
⇓ 
  BURNER IGNITION (SOFT) 
For a few seconds, the board conveys soft-ignition power to the modulation coil   
⇓ 
  FLAME DETECTION   
By means of the ionisation electrode, the ignition cardt detects burner ignition and conveys 
the burner ignition signal to the modulation board 
⇓ 
  BOILER OPERATION   
  The burner operates at an output that varies according to the type of request, the 
adjustments/settings made and the temperatures read by the NTC sensors 










