As the heating sensor reaches temperature
the fan speed modulates to maintain the
temperature set on the display panel.
When starting, the fan will always start at the
set-point speed.
The boiler is
fi
tted with an anti-cycling device
on the control board. This delays the boiler
from re-
fi
ring within 10 minutes.
If the heating temperature goes 20 °C below
the set point, the burner restarts immediately.
The domestic hot water will always take
priority and is unaffected by the anti-cycling
device.
2.6
GENERAL FUNCTION
The instrument panel permits regulation of the
boiler to partial heating requirements, between
maximum and minimum settings.
Air and gas are drawn by the fan for
combustion.
The fan also forces exhaust gas through
the
fl
ue to the outside, this creates a lesser
pressure in the sealed combustion chamber,
thus sucking in combustion air, through the
inlet duct.
The boiler water temperature is automatically
controlled by a built in thermostat.
Interior space temperature is set by the room
thermostat to be installed in the heating
system. The boiler already carries connection
terminals for this thermostat, as well as for
a
external timer if required. The
external timer if required. The burner
continues to operate until it is stopped by the
digital clock or one of the thermostats.
When the internal C.H. temperature sensor
or the room thermostat intervenes the burner
shuts down. The fan stops but the pump
continues to operate for 3 minutes.
The boiler also incorporates an anti-block
system which powers the pump every 24
hours, allowing it to operate for 2 minutes if
the boiler has not been in use. This operation
may in some cases be heard for a short
period when the pump has been activated.
The heat exchanger in the D.H.W. circuit is
a stainless steel plate heat exchanger water
to water, and domestic water is heated by
converting the water in the central heating
circuit. The transfer of heat is very high
because the two
fl
uids move in a counter
direction.
Select the winter position by summer/winter
button (item 1
fi
g. 1).
2.2
INTRODUCTION
This boiler is designed for the production of
central heating and domestic hot water
combined in one unit.
It is
fi
tted with an automatic domestic hot
water priority valve.
It is possible to select either a summer or
It is possible to select either a summer or
winter function.
winter function.
With the summer position only being for
With the summer position only being for
domestic hot water.
domestic hot water.
The winter position being for central heating
The winter position being for central heating
with domestic hot water priority.
with domestic hot water priority.
2.3
2.3
DESCRIPTION OF CONTROL SYSTEM
DESCRIPTION OF CONTROL SYSTEM
AND SEQUENCE OF OPERATION
AND SEQUENCE OF OPERATION
2.4
Domestic hot water mode
2.4
Domestic hot water mode
When the appliance is in rest mode,
When the appliance is in rest mode,
select the summer position by pressing
select the summer position by pressing
the ON/OFF button (item 1 fig. 1) please
the ON/OFF button (item 1 fig. 1) please
ensure that the heating circuit is charged
ensure that the heating circuit is charged
with water (above 1 bar).
with water (above 1 bar).
If the domestic hot water tap is turned
If the domestic hot water tap is turned
on the boiler will function in the
on the boiler will function in the
following sequence:
following sequence:
The pump starts.
The fan starts and sends a
signal back to the ignition board that the fan is
running.
The spark ignition system is powered which in
turn commences the spark igniter to operate
and light the burner.
At this point the ignition board opens the gas
valve to light the burner.
When the electrode sensor senses the signal
that the burner is alight, the spark igniter
stops.
The fan speed settings on the boiler increases
The fan speed settings on the boiler increases
to the maximum permissible speed over
to the maximum permissible speed over
a period of 5 seconds and will remain at its
a period of 5 seconds and will remain at its
maximum required power until its maximum
maximum required power until its maximum
regulated temperature is achieved and then
regulated temperature is achieved and then
will modulate to maintain this.
will modulate to maintain this.
When the domestic hot water tap is closed the
When the domestic hot water tap is closed the
diverter valve goes back into rest mode, the
diverter valve goes back into rest mode, the
burner is shut down along with the fan which is
burner is shut down along with the fan which is
also switched off.
also switched off.
2.5
Central heating mode
2.5
Central heating mode
If the appliance is in winter mode with a
If the appliance is in winter mode with a
demand for heat to supply radiators, etc. ,
demand for heat to supply radiators, etc. ,
with the heating circuit fully cha
with the heating circuit fully charged above
1 bar, so as to operate the low water sensor
device the boiler will start in the same way
as domestic hot water mode.
12
