Supplied By www.heating spares.co Tel. 0161 620 6677
SECTION 1
INTRODUCTION
1.1
The
Ravenheat boiler is for the use of cen-
tral and domestic hot water combined in
one unit.
It is fitted with an automatic domestic hot
water priority valve.
A winter/summer selector switch is fitted to
the left hand side of control panel. With the
only summer position being for domestic hot
water.
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 front cover.
1.2
Fig. 1 Illustrates the general layout of
components.
Fig. 2 Illustrates the operating principles
described in section 2.
SECTION 2
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
DESCRIPTION OF CONTROL SYSTEM
AND SEQUENCE OF OPERATION
Domestic hot water mode
When the appliance is in rest mode with the
mains neon switch on. Switch the sum-
mer/winter switch in the summer Position,
making sure the heating circuit is charged
with water (above 1 bar). When the domes-
tic hot water tap is turned on, the boiler will
function in the following sequence:
The pump starts.
The control board sensors.
The fan operates via the pressure switch and
sends a signal back to the ignition board that
the fan is running at maximum speed.
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 sig-
nal the burner the spark igniter stops.
From the minimum gas rate setting the boil-
er increases to the maximum permissible
pressure over a period of 3 to 4 seconds and
will remain at its maximum required power
until its maximum regulated temperature.
When the domestic hot water tap is closed
the diverter valve goes back into rest mode,
the main burner is shut down. The pump
and fan are also switched off, the pressure
switch returning to its rest mode.
2.2.6
2.2.7
2.2.8
2.2.9
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
2.3.7
Central heating mode
If the switch is positioned on winter with a
demand for heat to supply radiators, etc.
With heating circuit fully charged so as to
operate the low water sensor device the
boiler will start in the same way as domes-
tic hot water mode but with slightly differing
time delay in that it will start on minimum
and remain at this level for about 1 minute,
after which the flame will lift to its maximum
setting as governed by a potentiometer
range rates the heating circuit between
maximum and minimum power.
On the control panel are mounted two
potentiometers (thermostats) these control
the temperature. One is for domestic hot
water and the other for heating.
The boiler is fitted with an anti-cycling
device on the control board. This delays the
boiler from re-firing over a 2.5 minute period
when in heating mode. The domestic hot
water will always take priority and is unaf-
fected by the anti-cycling device.
GENERAL FUNCTION
Central Heating Mode
A potentiometer is installed on the electric
circuit board permits regulation of the boiler
to partial heating requirements, between
the factory setting.
Air is drawn by the fan for combustion.
The fan also forces exhaust gas through the
flue to the outside, this creates a lesser
pressure in the sealed combustion cham-
ber, thus sucking in combustion air, through
the inlet duct.
The boiler water temperature is automati-
cally controlled by a built in thermostat.
Interior space temperature is set by the
room thermostat to be installed in the heat-
ing system. The boiler already carries con-
nection terminals for this thermostat, as
well as for a timeclock. The burner will con-
tinue to operate until it is stopped by the
timer or one of the thermostats.
When the internal C.H. temperature sensor
intervenes the main burner shuts down. The
fan stops but the pump continues to oper-
ate.
When the room thermostats intervene the
main burner shuts down. The fan stops and
the pump turns off.
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