Technical documentation
Technical documentation
STEM@ ed 06/01
19
EOLO MAIOR @
Circulator (M1)
This is powered by the modulation card whenever there is a demand for d.h.w., heating
or antifreeze.
Permits circulation of water in the primary circuit.
Ignition electrodes
(E1 - E2)
These provoke an electric spark that ignites the air-gas mix.
They are controlled from the ignition unit (IGN. BOARD).
Modulation card
This is powered when the main switch is positioned on
(summer)
or
(winter)
(see modulation board operation).
Gas valve (Y1)
(main coils)
This is powered by the ignition circuit when the burner has to be ignited.
Permits flow of gas to the burner.
Fan
(M2)
Ensures air flow inside the sealed chamber and exit of combustion flue.
Powered by the ignition card.
LOW-VOLTAGE CIRCUIT
SAFETY DEVICES AND CONTROLS
Zone control unit (CZ)
(external optional)
Permits boiler operation with 3 area valves or external pumps
controlled by the respective room thermostats.
Area 1 controls (
times and temperatures)
through the CAR.
See control zone
unit operation
Remote control (CAR)
(external optional)
Permits remote control of boiler
(SUM/WINT switch, temperature
adjustment and indication, alarm display, reset, etc.)
and acts as a
weekly chronothermostat.
See Remote
Friendly Control
Operation
(CAR)
Depending on position, permits :
Main switch
(S5)
0
RESET
-
low-voltage circuit not powered
-
d.h.w. operation
(combined models only)
and CAR
(optional)
- d.h.w. and central heating operation
- release after tripping of ignition failure, temperature and
stack safety device
(the RESET position works at the mains
voltage by closing a contact that controls the ignition unit
)
3 position double
reset
button
D.h.w. switch (S6)
(combined models only)
Following an hot water request
, this affects the adjustment board,
causing the pump (M1) to operate and enabling the burner pump.
When idle, it enables operation in central heating mode.
Two-contact
switch
System water pressure
switch
(S7)
This affects the modulation board and interrupts power to the circulator
(M1) and to the ignition unit when the pressure in the boiler circuit is
below 0.3 bar.
Two-contact
switch
Central heating sensor
(B1)
Permits the modulation card to read the temperature of the delivery
water in the primary circuit.
If this breaks, burner operation will be stopped in both central heating
and d.h.w. mode.
This is located at the exit of the main exchanger.
NTC sensor
10 kohm 25 ºC
D.h.w. sensor (B2)
(combined models only)
Permits the modulation board to read the outlet temperature of the
d.h.w.
If this breaks, burner operation will be stopped in d.h.w. mode.
This is located in the d.h.w. pipe at the plate exchanger exit.
NTC sensor
10 kohm 25 ºC
LOADS
Modulation coil
(Y2)
This is powered by the modulation board with variable DC current.
Permits changing the gas pressure to the burner.