Immergas ZEUS Maior - Low Voltage Circuit

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STZM@ ed 05/04 ZEUS Maior @
Technical DocumentationTechnical Documentation
Low voltage circuit.
anks to this unit the boiler can work with 3 zone valves or external
pumps controlled by the relative room thermostats.
Zone 1 is controlled (times and temperatures) by CAR (if in-
stalled).
Zones control unit (CZ)
(external optional)
is device is to control the boiler remotely (SUMMER / WINTER
switch, setting and indicating temperatures, displaying alarms, resetting,
etc.) and acts as a weekly timer/room thermostat.
Remote Control
(CAR)
(external optional)
See Remote Con-
trol operation
(CAR)
See zones control
unit operation
Depending on the position it is in it allows:
0 Low voltage circuit not powered.
( ) D.h.w. and CAR operation (optional).
( ) D.h.w. and central heating operation.
RESET Resets after an ignition failure or if the overtemperature
safety device trips (the RESET position works at mains voltage closing
a contact that acts on the ignition control unit).
Main switch (S5)
Double 3-posi-
tion switch + reset
push button
It lets the modulation board measure the temperature of the delivery
water in the primary circuit.
If it breaks the burner stops working whether in the central heating
or d.h.w. mode.
It is located on the main exchanger outlet.
Delivery probe
(B1)
NTC probe
10 kohm 25°C
It lets the modulation board measure the outlet temperature of the
hot water in the storage tank.
If it breaks its stops the burner working in the domestic hot water
mode.
It is inside a hole on the outside wall of the storage tank to which
it is fixed.
D.h.w. probe
(B2)
NTC probe
10 kohm 25 °C
It enables operation in the central heating mode when room tem-
perature is below that required.
If CAR is installed the thermostat has to be disconnected without
restoring the X20 jumper.
Room thermostat (TA)
(external optional)
Interrupted
contact
It is powered by the modulation board with a variable continuous current.
It allows gas pressure to the burner to be varied.
Gas valve modulator
(Y2)
Loads.
It acts on the modulation board cutting power off to the circula-
tor (M1) and to the ignition control unit when the pressure in the
boiler circuit is below 0.3 bar.
System pressure switch
(S7)
Interrupted
contact