2748
8
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 minimum 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 EN 676 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
When flame-failure occurs during working, shut down takes place within one second.
4.7
START-UP CYCLE DIAGNOSTICS
During start-up, indication is according to the followin table:
COLOUR CODE TABLE
Sequences
Colour code
Pre-purging
● ● ● ● ● ● ● ● ● ● ●
Ignition phase
● ❍ ● ❍ ● ❍ ● ❍ ● ❍ ●
Operation, flame ok
❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑
Operating with weak flame signal.
❑ ❍ ❑ ❍ ❑ ❍ ❑ ❍ ❑ ❍
Electrical supply lower than
~
170V
● ▲ ● ▲ ● ▲ ● ▲ ● ▲ ●
Lock-out
▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲
Extraneous light
▲ ❑ ▲ ❑ ▲ ❑ ▲ ❑ ▲ ❑ ▲
Index:
❍
Off
●
Yellow
❑
Green
▲
Red
Lock-out, due to ignition failure
Normal
Thermostat
Motor
Ignition transformer
1st
stage valve
1st
stage flame
2nd
stage valve
2nd
stage flame
Lock-out
max. 3s
max. 3s
40s
40s
10s
max. 2s
max. 2s
D4170
