22
STEMkW Special ed 01/08 EOLO Mini kW Special
Technical DocumentationTechnical Documentation
After some d.h.w. has been drawn this switch acts on the integrated
P.C.B. provoking operation in the domestic hot water mode.
When idle it enables operation in the central heating mode.
D.h.w. ow switch
(S4)
Interrupted
contact
Powered by the P.C.B. with variable continuous current.
It varies gas pressure to the burner.
Gas valve modulation coil
(Y2)
Loads.
Depending on its position the main switch allows:
= Powered circuit, post-ventilation function is ended.
( ) = DHW and CAR function (optional).
( ) = DHW and central heating function.
RESET = Operate after a ‘no ignition’ or safety device has triggered,
it enables chimneysweep function, and provides access to boiler
parameters setting.
Main switch (R10) Trimmer
When safety temperature is exceeded (105 °C), the safety thermostat
switches the burner o.
e probe is located on the main exchanger outlet.
Safety thermostat
(E4)
Klixon thermostat
with normally
closed contact
It allows the integrated P.C.B. to feel temperature of ow water in
the primary circuit.
Should the probe malfunction, the burner is shut down preventing
both central heating and DHW operation.
e probe is located on the main heat exchanger outlet.
Flow probe
(B1)
NTC probe
10 kΩ 25 °C
It enables operation of central heating mode when room tempera-
ture is below temperature set value.
When CAR is installed, the room thermostat must be disconnected
without re-connecting the pre-existing X40 jumper.
Room thermostat (S20)
(optional)
Disconnecting
contact
It senses outdoor temperature and allows for the P.C.B. to change
CH ow temperature in relation to outdoor temperature.
If the boiler is controlled by CRD, the outdoor probe will not
operate.
External probe
(B4) (optional)
NTC probe
1 kΩ 25 °C
It signals that ue is properly discharged to the integrated P.C.B.
which enables burner operation.
If its contacts are closed while the fan is switched o, it will not
enable the ignition cycle.
Flue pressure switch
(S6)
Changing contact
To Next Page
Loading...
