Technical data

Technical documentation

STZS ed. 06/03

ZEUS SUPERIOR

MODULATION BOARD

The boiler is equipped with a microprocessor-controlled electronic board used on both the models with

3-way electric valve (Zeus Superior, Eolo Superior Plus) and on the models with central-heating and

d.h.w. pumps (Hercules).

The different type of operation is obtained by adjusting diode D9 (diode engaged = electric 3-way valve,

diode disengaged = double pump).

The board is connected to a terminal board (DISPLAY CARD) which, by means of LEDs and a display

panel, indicates the state of operation of the appliance.

The board is powered with main switch (IG) in position

(summer) or (winter).

Central-heating request with room thermostat

With the main switch (IG) in WINTER position and the contact of the room thermostat (TA) closed, the low-

voltage circuit starts the circulator (MP) by means of relay “K2” and powers the motor (M) of the 3-way

valve (VD) through the contact of relay “K3”.

The circulation of water results in the closing of the pump pressure switch (SP) which, because it is connected

in series to the NC contact of the flue pressure switch (SV) powers the coil of relay “K5”.

If the temperature detected by means of NTC central heating sensor (NR) is below that set on the control

panel by means of the central heating potentiometer (HEATING), the adjustment circuit excites relay “K5”

and starts the fan (MV) controlled by relay “K1”.

The consequent deviation of the contact of the flue pressure switch (SV) results in relay “K4” being powered

and the relevant contact closing.

This powers the control unit (IGN. UNIT) and starts the ignition cycle.

During the ignition phase, the current to the modulation coil is restricted by the adjustment made with the soft

ignition trimmer (POT ACC.).

Once the flame has been detected (signal from control unit), the signal to the coil (MOD) is changed in a

manner directly proportionate to the difference between the temperature set with the central-heating

potentiometer (HEATING) and that detected by means of the NTC central-heating sensor (NR) and, if

necessary, reaches maximum set value in 50 seconds (maximum central-heating output).

When the set value is exceeded, the contact of relay “RT” is opened with consequent switch-off of the burner.

Re-ignition of the burner for the same request remains inhibited for 180 s / 30 s.

Central-heating request with Remote Friend Control

If the conditions detected by the remote control (CAR) require ignition in central-heating phase (SUM/WINT

switch of CAR in WINTER position, time programmer request, room temperature setting above that found),

the low-voltage circuit starts the circulator (MP) by means of relay K2 and powers the motor (M) of the 3-

way valve (VD) by means of the contact of relay “K3”.