22
STEEkW ed 12/03 EOLO Eco kW
23
STEEkW ed 12/03 EOLO Eco kW
Technical Documentation
Technical Documentation
Technical Documentation
Technical Documentation
Inputs.
It sends signals to the board of the SUMMER/WINTER selector switch concerning d.h.w.
and central heating temperature adjustment and the central heating request
(times, room
temperature, error codes, etc…).
Remote control
(CAR)
(optional)
(see CAR operation)
It sends signals to the board concerning operating requests of zone valves or connected
external pumps
(see zone control unit operation).
Zone control unit (CZ)
(external optional)
When the primary circuit pressure is below 0.3 bar, it cuts power
to the K2 relay, preventing the ignition cycle starting.
System pressure switch
(S5)
open =
low pressure
closed =
pressure OK
It enables burner ignition, powering the K2 relay when the flue
are expelled correctly.
If the “NO” contact is closed with the fan off, it does not enable
the start of the ignition cycle.
Flue pressure switch
(S6)
Switching
contact
It is a signal that indicates flame detection.
It lets the board increase current to the modulation coil (Y2) after having limited it during
the ignition phase.
It keeps the gas valve (Y1) open.
Flame detection
It is a resistor that varies in a proportionate way to the external
temperature.
It enables to change the system delivery temperature in accordance
with external temperature.
External probe (B4)
(optional)
PTC probe
1 kohm 25 °C
It indicates which request is ongoing
(d.h.w. or central heating).
After domestic hot water has been run, it enables operation of the
boiler in the domestic hot water phase which is given priority with
respect to the system central heating phase.
D.h.w. flow switch
(S4)
Closed = d.h.w.
request
Open = central
heating request
It is a resistor inversely proportionate 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 inversely proportionate to the outlet temperature of
the domestic hot water.
D.h.w. probe
(B2)
NTC probe
10 kohm 25 °C
It is a switch with free contacts that sends a
(low voltage)
signal to
the board, enabling operation in the central heating phase when
room temperature is below that requested.
Room thermostat
(S20)
(external optional)
Open = Central
heating OFF
Closed = Central
heating ON
is is a free contact switch, controlled by a clock that enables or
prevents boiler operation in the central heating phase at the set
times.
Central heating timer
switch
(P1)
(external optional)
Open = Central
heating OFF
Closed = Central
heating ON
