20017633
11
GB
4.5
AIR PRESSURE SWITCH
The air pressure switch is set after all other adjustments have been made. Begin with the switch at the
lowest setting. With the burner working at the required output, adjust the dial clockwise, increasing its value
until the burner shuts down. Now reduce the value by one set point, turning the dial anti-clockwise. Check
for reliable burner operation, if the burner shuts down, reduce the value by a half set point.
ATTENTION:
To comply with the standard, the air pressure switch must operate when the CO value exceeds 1%
(10,000 ppm). To check this, insert a combustion analyser in the flue, slowly reduce the burner air setting and
verify that the burner shuts down by the action of the air pressure switch before the CO value exceeds 1%.
4.6
BURNER START-UP CYCLE
Lock-out is indicated by a lamp on the control box (4, fig. 1, page 2).
4.7
RE-CYCLE FUNCTION
The control box allows re-cycling, i.e. the complete repetition of the starting programme, for 3 attempts maxi-
mum, in the event the flame goes out during operation.
4.8
POST-VENTILATION FUNCTION
Post-ventilation is a function that maintains air ventilation even after the burner is switched off. The burner
switches off when the limit thermostat (
TL
) opens, cutting off the fuel supply to the valves.
To use this function the reset button must be pressed when the limit thermostat is not switched over
(
BURNER SWITCHED OFF
).
Post-ventilation time can be set to a maximum of 6 minutes. Proceed as follows:
Press and hold the reset button for at least 5 seconds till the LED indicator changes to red.
Set the desired time pressing the button repeatedly:
once = post-ventilation for 1 minute
.
After 5 seconds the control box automatically shows the minutes set by the red LED flashing:
1 pulse = post-ventilation for 1 minute
.
To reset this function, press and hold the button for at least 5 seconds the LED indicator changes to red then
release it without carrying out any operation, then wait for 20 seconds for the burner to start.
If during post-ventilation there is a new request for heat, post-ventilation time is halted and a new operating
cycle starts when the limit thermostat (
TL
) switches over.
The control box leaves the factory with the following setting:
0 minutes = no post-ventilation
.
4.9
CONTROL BOX RESET
To carry out the control box reset, proceed as follows:
Press the reset button for at least 1 second.
In the event of the burner not restarting it is necessary to check if the limit thermostat (
TL
) is closed.
Thermostat
Motor
Ignition transformer
First valve
First flame
Second valve
40s min.
3s max.
40s min.
3s max.
Lock-out, due to light failure
A
Normal
Second flame
Lock-out
5 – 25s
D5016
A
