27
STEkW ed 12/06
EOLO Maior kW
Technical Documentation
Technical Documentation
Depending on the position it allows:
= With the circuit powered, the antifreeze and antilock
functions remain active, the various post-circulation and post-
ventilation functions are terminated.
(
) = Domestic hot water function and CAR
(optional).
(
) = Domestic hot water and central heating function.
RESET
= Reset after an ignition failure or if the overheating safety
device triggers, it allows the chimney sweep function to be activated,
it allows access to boiler parameter setting.
Main selector switch (R10)
Trimmer
If the safety temperature is exceeded (105 °C) the burner switches
off.
It is positioned on the main exchanger outlet.
Safety thermostat
(E4)
Clicson thermo-
stat with normally
closed contact
It lets the integrated board detect the temperature of the primary
circuit delivery water.
If it breaks, burner operation stops in both the central heating and
domestic hot water mode.
It is positioned on the main exchanger outlet.
Delivery NTC probe
(B1)
NTC probe
10 kohm 25 °C
Allows the electronic control board to read the outlet temperature
of the domestic hot water.
The sensor fault is signalled by the flashing of Led 10 ( ), the
boiler keeps working in d.h.w. mode.
It is mounted on the d.h.w. outlet body connected to the d.h.w.
plate exchanger.
For kW X models:
It is inserted inside a bulb holder in contact
with the external wall of the separate storage tank eventually con-
nected.
D.h.w. NTC probe
(B2)
(optional kW X version)
NTC probe
10 kohm 25 °C
It is powered by the integrated board with a variable d.c.
With this the pressure of the gas to the burner can be varied.
Gas valve modulator
(Y2)
Loads.
It acts on the integrated board and enables boiler operation when
the flue are extracted correctly.
If it is closed with the fan off it does not enable start of the igni-
tion cycle.
Flue pressure switch
(S6)
Switching
contact
It detects the external temperature and lets the board change system
delivery temperature according to it.
External probe
(B4)
(optional)
PTC probe
1 kohm 25 °C
It acts on the integrated board enabling operation of the boiler in
the central heating phase at the selected times.
If it is mounted alone, connection is to terminals 40 and 41 of the
X14 connector after having removed jumper X40.
If it is mounted together with a room thermostat (S20) it is con-
nected to terminals 8 and 41 of the X14 connector after having
removed jumper X40.
Central heating timer (P1)
(external optional)
Interrupted
contact
It enables operation in the central heating phase when room tem-
perature is below that requested.
If the CAR device is installed, the room thermostat must be discon-
nected without re-establishing the existing jumper X40.
Room thermostat (S20)
(external optional)
Interrupted
contact
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