Central Heating
To be able to supply heating, the main switch 15 must be
turned fully clockwise to
position. This will be confirmed
by the green indicator light
20.
When there is a demand for heating (either from the room
thermostat or the external programmer) and the boiler tem-
perature control is calling for heat. The pump starts and at a
flow rate of 4 ltr/min the central heating flow switch operates
allowing the ignition sequence to begin.
The first stage solenoid 31 (blue) and security solenoid 30
(grey) 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
21 will light.
After 45 seconds the second stage solenoid 32 (black) opens
to allow the full gas rate.
If a flame is not detected, after 8 seconds, the security sole-
noid closes and shuts off the gas
The red lockout indicator bulb
22 Fig. 6 will light.
The central heating flow temperature is controlled by the cen-
tral heating control thermistor 37.
The boiler has been designed to minimise cycling and will not
attempt to relight for at least 3 minutes after the boiler ther-
mostat has been satisfied If used with a cylinder, the delay
must be set to 20 seconds (refer to adjustments on control
PCB).
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..
NB
It is possible to override the 3 minute delay by pressing the
RESET button 23
Lock out procedure
Flame disappearance :
When the ionisation electrode 28 does not detect flame pres-
ence, the orange indicator lamp 21 extinguishes.
A lighting cycle starts.
If a flame is not detected before 8 seconds, the grey security
solenoid 30 and the blue 1/3 solenoid 31 will close.
The lock out red indicator 22 lights, the pump 35 runs.
After a few seconds, it will become possible to reset the boil-
er by pressing the reset button 23.
Overheat detection :
If an overheat is detected by the sensor 13, the grey security
solenoid 30 and the blue 1/3 31 closes, the orange indicator
lamp
21 extinguishes.
The ignitor is energised for 8 seconds (*) and the red lockout
indicator 22 lights.
(*) If the burner cannot relight the boiler will go to lockout.
4
Plug for main power and Room
thermostat connection
1
2 3
4
5
1. Neutral
2. Phase
3. Room thermostat live
4. Accelerator resistor
5. Common for Accelerator and room
thermostat.
WIRING
DIAGRAM
Summary of Contents for BRITONY System II 80
Page 11: ...Notes ...
