4
Switching On the Domestic Hot Water and Central Heating Together
Press the key 29, the green indicator 30 will light.
Press the key
25, the green indicator 26 will light.
If there is no water demand
the display will show the heating flow temperature
During
draw off a square made of 4 digits will move clockwise on the display
Turn Off the Boiler
- Press the key 29 and the key 25, to switch off both the D.H.W. and C.H. mode. The green indicators 30 and 26 will
go off.
- Switch off the main electrical supply
- Shut off the gas service tap
39 (Fig. 21)
Note : In this condition, the anti-freeze system is inoperative.
Stand-by Mode A fixed digit at the centre of the display and the green indicator 33 will illumi
nate.
Putting the boiler in stand-by mode and anti-freeze system. :
Press the key 29 and the key 25, to switch off both the D.H.W. and C.H. mode. The green indicators 30 and 26
will go off.
During the duration of the stand by mode, an automatic anti-sticking system will activate the pump and 3 way valve
for 1 minute every 23 hours.
The stand by mode will disable the anti-freeze function of the room thermostat (if fitted). To leave the room thermostat anti-freeze system operative, leave the Central Heating mode on.
The boiler is equipped with an automatic anti-freeze system which is permanently on.
If the Central Heating temperature falls below 7°C, the pump will start.
If the Central Heating temperature falls below 4°C, the pump and the burner will start.
Domestic Hot Water Mode
To be able to supply Hot Water, the
D.H.W. mode should be ON. Press the
key
25, the green indicator 26 will
illuminate.
If there is no water demand, the display
will show the following graphic
During draw off, a square made of 4 digits will move clockwise on the display
.
Keys
27 and 28 allow the tem-
perature to be adjusted as required for
D.H.W. flow. During the temperature setting operation, the display will flash.
When a tap or a shower is turned on, a
flow of mains water above 2 l/min, will
activate the D.H.W. flow switch
20, the 3
way valve 17 will move to the D.H.W.
position. The pump can now circulate primary water heated by the main exchanger through the secondary heat
exchanger. The C.H. flow switch checks
that the flow rate is over 4 l/min to allow
the ignition sequence to begin.
The fan on the gas valve assembly starts
and when the lighting speed is reached
(detected by a hall effect sensor) the 2
safety solenoids open together to allow
gas to the burner. The ignition sequence
begins and a continuous high speed
spark ignites the gas. As soon as a flame
is detected, the orange indicator bulb
34
will light and the regulation system will
be able to adjust the gas rate according
to the heat load. If a flame is not detected, after 10 seconds, the security solenoids close together and shut off the
gas. The red lockout indicator bulb 35
will light. Press the reset button to reattempt ignition.
The Domestic Hot Water temperature is
controlled by the Hot Water control thermistor
22 and the Central Heating control
thermistor 21. The system anticipates
changes of temperature in the secondary
heat exchanger and ensures accurate
temperature regulation.
When the tap is closed, the burner is
extinguished and the pump stops. The
boiler will now stay in the Hot Water
mode for 3 minutes to maintain temperature and to ensure a fast response in
the event of a subsequent Hot Water
demand.
Priority will be given to a demand for Hot
Water. This will interrupt the Central
Heating for the duration of Hot Water
delivery.
Central Heating Mode
To be able to supply Central Heating, the
C.H. mode should be switched ON.
Press the key
29, the green indicator
30 will light, and the display will show the
Heating Flow temperature.
Keys
31 and 32 allow the tem-
perature to be adjusted as required for
the Central Heating system relating to
the weather conditions. During the setting operation, the display will flash.
When there is a demand for heating,
(either from the room thermostat or the
clock) the pump starts. If the boiler temperature control is calling for heat and
the Central Heating flow rate is over 4
l/min, the Central Heating flow switch
operates, allowing the ignition sequence
to begin. The fan on the gas valve
assembly starts and when the lighting
speed is reached (detected by a hall
effect sensor) the 2 safety solenoids
open together to allow gas to the burner.
The ignition sequence begins and a continuous high speed spark ignites the gas.
As soon as a flame is detected, the
orange indicator bulb
34 will light and the
regulation system will be able to adjust
the gas rate according to the heat load. If
a flame is not detected after 10 seconds,
the security solenoids close together and
shut off the gas. The red lockout indicator bulb
35 will light. Press the reset but-
ton to re-attempt ignition.
The Central Heating flow temperature is
controlled by the Central Heating control
thermistor
21. The boiler has been
designed to minimise cycling and will not
attempt to re-light for at least 3 min. after
the boiler thermostat has been satisfied.
When the room thermostat is satisfied,
the burner will switch off and the pump
will run for a further 3 minutes before
stopping.
Note:
It is possible to override the 3 minute
delay by pressing the reset button 36.