25
STNM ed 07/07
NIKE Mini Export
Technical Documentation
Technical Documentation
Electrical circuit.
D.h.w. phase.
(*) depending on the gas valve used, the main coils are powered
at mains voltage (SIT 845) or at mains voltage rectified by a
diode bridge (U1) housed in the valve connector (Honeywell
VK4105).
Operation.
By selecting the
(Summer) or (Winter), functioning
mode with the (S2) push button, the boiler is enabled to work
in the d.h.w. mode.
When some domestic hot water is drawn it causes the contact
of the d.h.w. flow switch (S4) to close. Subsequently, if the
temperature measured by the NTC delivery probe (B1) is below
the d.h.w. value set on the boiler’s control panel
(or on the CRD
if mounted)
, the integrated board powers the boiler circulator
(M1) by means of the K3 relay and, with the deviation of the
K1 relay contact, powers the motor (M) of the 3-way valve
(M30) which keeps working until limit switch “3” opens when
the d.h.w. position is reached.
The integrated board, enabled by the safety thermostat (E4)
and fumes thermostat (E6), closes the contact of the request
relay K2 that causes the 2 contacts to close which allows the
ignition cycle to start, first of all triggering the ignition elec-
trode (E1) and then both the gas valve coils (Y1).
Burner ignition is detected by the integrated board by means
of the ionisation electrode (E2).
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