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6
etc ,with heating circuit fully charged so as to
operate the low water sensor device the boiler
will start in the same way as domestic hot water
mode .
As the heating sensor reaches temperature
the fan speed modulates down.
When starting, the fan will always start at the
set-point speed.
2.2.8
On the control panel are mounted two
potentiometers (thermostats) these control
the temperature. One is for domestic hot
water and the other for heating.
2.2.9
The boiler is fi tted with an anti-cycling device
on the control board. This delays the boiler
from re-fi ring over a 10 minute.
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.
GENERAL
FUNCTION
2.3
Central Heating Mode
2.3.1
A potentiometer installed on the panel
instruments permits regulation of the boiler
to partial heating requirements, between
maximum and minimum settings.
2.3.2
Air is drawn by the fan for combustion.
2.3.3
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.
2.3.4
The boiler water temperature is automatically
controlled by a built in thermostat
2.3.5
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
timeclock.
The burner continues to operate until it is
stopped by the timer or one of the thermostats
2.3.6
When the internal C.H. temperature sensor
intervenes the burner shuts down. The fan
stops but the pump continues to operate.
2.3.7
When the room thermostats intervene the
burner shuts down. The fan stops and the
pump after 3 minutes turns off.
2.3.8
In summer position an anti-block of the pump
is included. Every day the pump is powered for
a period of 2 minutes.
The boiler also incorporates an anti-block
system which powers the pump every 24
hours, allowing it 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.
SECTION 1
INTRODUCTION
1.1
The Ravenheat boiler is for the production
of central and domestic hot water combined
in one unit.
It
is
fi tted with an automatic domestic hot
water priority valve.
A Summer/winter switch is fi tted to
the left hand side of the control panel.
With the Summer only switch position being
for domestic hot water.
The summer/winter position being for
central heating with domestic hot water
priority.
The boiler is equipped with a front cover
which can be removed for servicing. The
data badge with technical data is placed on
the lower part of the left hand side panel.
1.2
Fig.1 Illustrates the general layout of
components.
Fig.2 Illustrates the operating princi-
ples described in section 2.
SECTION 2
2.1
DESCRIPTION OF CONTROL SYSTEM
AND SEQUENCE OF OPERATION
2.2
Domestic hot water mode
When the appliance is in rest mode with
the mains neon and switch on.
Switch the summer/winter switch to
Summer position, with the heating circuit
charged with water (above 1 bar). If the
domestic hot water tap is turned on,
the boiler will function in the following
sequence:
2.2.1
The pump starts.
The fan starts and sends a signal back to the
ignition board that the fan is running .
2.2.2
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.
2.2.3
When the electrode sensor senses the signal
of the burner, the spark igniter stops.
2.2.4
From the fan speed setting the boiler
increases to the maximum permissible speed
over a period of 5 seconds and will remain at
its maximum required power until its maximum
regulated temperature.
2.2.5
When the domestic hot water tap is closed the
diverter valve goes back into rest mode, the
burner is shut down along with the fan which is
also switched off.
2.2.6
Central heating mode
2.2.7
If the switch is positioned on winter
with a demand for heat to supply radiators,
