4
Central Heating Mode
To be able to supply heating, the mode should be switched ON. Press on key 29
, the green indicator 30 will light, and the
display will show the Heating Flow temperature.
Keys 31
and 32
allow to adjust the temperature required for Central Heating system regarding 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 primary flow rate over 4 lt./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 led 34 will light and the regulation system will be able to adjust the gas
rate regarding 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 led 35 will light. Press the reset button to re-light the burner.
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 remain running for a further 3 minutes before it too stops.
Note
It is possible to override the 3 minute delay by pressing the Reset key 36
Lockout procedure
Flame disappearance :
When the ionisation electrode
8 does not detect flame presence. The orange indicator led 34 extinguishes. A lighting cycle starts. If
a flame is not detected, before 10 seconds, the safety solenoids will close. The lockout red indicator
35 lights and the display shows
the error code. The pump continues to run. After a few seconds, it will become possible to reset the boiler by pressing the reset
key
36.
Overheat detection :
If an overheat (over 100°C) is detected in the primary circuit by the sensor 23, the safety solenoids close and the fan stops. The
orange led
34 extinguishes and the pump remains running for 3 minutes. The reset will be possible when the primary temperature
will decrease under 76°C.