Technical data
Technical documentation 
Technical documentation
STZS ed. 06/03
25
ZEUS SUPERIOR
INPUTS 
Central-heating sensor 
(NR) 
This is a resistance that varies in a way inversely proportionate to the 
temperature of the water flow in the primary circuit. 
It is used as a limit thermostat (90 ºC). 
Sensor NTC 
10 kohm 25 ºC 
D.h.w. sensor 
(NB) 
This is a resistance that varies in a way inversely proportionate to the 
temperature of the water contained in the storage tank. 
Sensor NTC 
10 kohm 25 ºC 
External sensor (NE) 
(external optional) 
This is a resistance that varies proportionately to the outside 
temperature. 
It enables the modulation board to change the system flow 
temperatures in accordance with the outside temperature. 
Sensor PTC 
1 kohm 25 ºC 
Flame detection 
(FLAME) 
This is a signal from the ignition card indicating the flame has been detected. 
It enables the board to increase power to the modulation coil after restricting this during the 
ignition phase. 
Flame lock 
This is a signal from the control unit (IGN. UNIT) that indicates burner 
ignition failure. 
The alarm is displayed with an error code on the display board display 
panel (E01) or, if fitted, on the remote control (see CAR operation.). 
230 Vac = flame 
lock 
0 Vac = stand-by 
/ burner ON 
Flue pressure switch (SV) 
This enables burner ignition by powering the relay “K4” when flue 
extraction occurs correctly. 
If the "NO" contact is closed with fan off will fail to enable the start of 
the ignition cycle. 
2-position switch 
Main switch 
(IG) 
Indicates whether d.h.w. operation mode (SUMMER) or d.h.w. and 
central-heating mode (WINTER) are enabled. 
closed=WINTER 
open = SUMMER
Overheating lock 
(IC1) 
This is a signal which, through an optoinsulator, indicates input to the 
main coils of gas valve (V/G). 
This permits the board to pinpoint and indicate with an error code 
(E02) any operation of the safety overheat. thermostat (TS). 
230 Vac = coils 
powered 
0 Vac = coils not 
powered 
Pump pressure switch 
(SP) 
In case of locked pump or low pressure in the primary circuit, this 
does not enable burner ignition and interrupts power to relays “K4”  
and “K5”. 
Double-contact 
switch 
Remote control (CAR) 
(external optional) 
(see CAR operation) 
This sends SUM/WINT switch signals to the board relating to d.h.w. and central-heating 
temperature adjustment and central heating request (time ,room temperature). 
When the CAR is fitted, the room thermostat must be disconnected without restoring the 
pre-existing jumper P1. 
Reset button 
(PU1) 
When this is pressed, the circuit is released after the overheating and 
no-ignition safety device has tripped (100 ºC). 
If this is kept pressed during operation, the gas pressure is maintained 
at soft ignition level. 
If this is kept pressed for at least 10 seconds in the absence of any 
requests, when it is released the "chimneysweep" function is engaged. 
Double-contact 
button 
Room thermostat (TA) 
(external optional) 
This is a clean-contact switch that enables operation in central-heating 
phase, when the room temperature is below that requested. 
open = heating OFF 
closed = heating ON
Zone control unit (CZ) 
(optional) 
This sends signals to the board relating to operation requests for any connected zone valves 
/ external pumps (see control zone unit operation). 










