Immergas EOLO Star 23 kW, Technical Documentation Manual

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STESkW ed 05/06 EOLO Star 23 kW
Technical Documentation Technical Documentation
Modulation board.
Inside the boiler’s control panel is a microprocessor controlled
electronic board that controls the appliance’s electrical devices
and sees to the linear modulation of burner power.
The appliance’s functioning status is shown on a display, indi-
cating if any of its safety devices have triggered.
The same board is used on all models, whether they are the
conventional or sealed chamber (NIKE/EOLO Star kW)
types . The different boiler functioning modes are recognised
automatically by means of the appliance’s wiring.
The integrated board is always powered regardless of the operat-
ing position determined by the functioning button (S2).
The board executes a periodical self-check to make sure it is
working properly. During the central heating functioning
mode or with the boiler in Stand-by, this function is activated
every 18 hours from the last boiler check/powering. During
the d.h.w. functioning mode, this self-check starts within
10 minutes from the last time water was drawn and lasts 10
seconds.
NOTE: the boiler stops working (together with indications)
during the self-check operation.
Operation.
Central heating request.
By selecting the (Winter) functioning mode with the (S2)
push button the boiler is enabled to work in the central heat-
ing mode.
When the room thermostat (S20) closes the integrated board
powers the boiler circulator (M1) by means of relay K3.
In the meantime, if the flue pressure switch (S6) contact is
idle “NC”, the adjustment circuit powers the fan (M20) by
means of relay K4.
If the following conditions occur: the system pressure switch
contact (S5) is closed (pressure in the primary circuit higher than
the minimum value) , the safety thermostat (E4) is enabled, the
flue pressure switch contact (S6) is in “NO” position and the
temperature read by the NTC delivery probe (B1) is below the
value set on the boiler’s control panel, then the P.C.B. energises
the request relay K2 which causes the 2 contacts to close which
starts the ignition cycle.
During the first few seconds after the gas valve (Y1) has been
powered, the current to the modulation coil (Y2) is limited to
the predefined soft ignition current.
The burner will then go to the minimum set value (set in the
“Minimum Central Heating Power*” parameter), reaching the
maximum set value (if requested) (set in the “Maximum Cen-
tral Heating Power*” parameter) in a time set in the “Central
Heating Ramp Time*” parameter.
Subsequently, the signal is varied directly proportionate to the
difference between the temperature set on the boiler control
panel and the temperature read by the delivery probe (B1).
When the set temperature (+5°C) is exceeded, the contact of
relay K2 is opened and the burner is switched off. Re-ignition
time depends on how the “Central Heating Ignitions Timer”
parameter is set.
Each time the burner switches off the fan and pump keep
working for another 30 seconds.
* see Integrated board programming.
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