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STZM@ ed 05/04 ZEUS Maior @
Technical Documentation
Technical Documentation
Inputs.
It sends the SUMMER/WINTER selector, d.h.w. and central heating temperature adjustment
and the central heating request (time, room temperature, error codes, etc.) signals to the board.
If the CAR is installed the room thermostat (TA) has to be connected without restoring
the X20 jumper.
Remote control
(CAR)
(external optional)
(see CAR operation)
Flame block
is signal comes from the control unit and indicates burner igni-
tion failure.
e (red) LED H2 turns on to indicate this alarm condition and
code E01 is viewed on the CAR display (if mounted).
To reset boiler operation after this alarm, put the main switch (S5)
on the RESET position or press the RESET button on the CAR
(if mounted).
230 Vac = flame
block
0 Vac = stand-by /
burner ON
Gas supply valve
(Y1)
It is a 230 V ac signal that, by means of an optoisolator, indicates
that the main coils of the gas valve (Y1) are energised.
It allows the board to detect and signal flame presence and if the
overtemperature thermostat (E4) has tripped.
It allows current to the modulating coil to be limited for 5 seconds
in the ignition phase (see soft ignition setting trimmer).
230 Vac = coils
energised
0 Vac = coils not
energised
It sends signals to the board referring to operation requests of zone valves/connected
external pumps (see zones control unit operation).
Zones control unit (CZ)
(external optional)
Main switch
(S5)
It is a double switch that, depending on its position, powers or does
not power the low voltage circuit (24 Vdc) and indicates whether
d.h.w. operation + CAR (SUMMER) or d.h.w. and central heating
(WINTER) is enabled.
Switch S5 B3
open = circuit
OFF
closed = circuit
ON
Switch S5 B3 =
SUMMER
Switch S5 B4 =
WINTER
When the pressure in the primary circuit is below 0.3 bar it cuts
power to the K2 relay preventing the burner from working.
e (yellow) LED H1 and (red) LED H2 flash alternately to in-
dicate this condition and code E10 is viewed on the CAR display
(if mounted).
ree minutes after power is cut, the board turns the circulator
(M1) off as well, cutting power to the K1 relay.
Subsequently, if the contact does not reclose, the circulator (M1)
is started for 15 s at 45 s intervals for up to a maximum of 60
times.
System pressure switch
(S7)
Open =
no pressure
Closed =
pressure OK
It is a resistor that varies in an inversely proportionate way to the
temperature of the primary circuit delivery water.
It is used as a limit thermostat (90°C).
Delivery probe
(B1)
NTC probe
10 kohm 25 °C
It is a resistor that varies in an inversely proportionate to the tem-
perature of the water contained in the storage tank.
D.h.w. probe
(B2)
NTC probe
10 kohm 25 °C
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