analyser 2cm into the heat exchanger and
measure the CO
2
level. The burner will
have a red surface. If necessary fine tune
using the adjusting screw 4 Q Max until the
required CO
2
(see table 15) value is
reached. Turn the screw clockwise to lower
the CO
2
reading and anti clockwise to
increase the CO
2.
Remember to allow 2 minutes for the
analyser to respond to any adjustments.
Figure 35
Gas valve adjustments
To obtain the minimum load, press the "-"
button until the minimum speed has been
obtained
Measure the CO
2
level. (This reading should
be 9.2% for NG and 11.0 for LPG). The
colour of the flame should be red/blue with
small sharp cones and without any flame
lifting. If necessary fine tune using the
adjusting screw 3 Q Min until the CO
2
value
is reached. Turn the screw anti clockwise to
lower the CO
2
reading and clockwise to
increase the CO
2.
Remember to allow 2 minutes for the
analyser to respond to any adjustments.
T
T
a
a
b
b
l
l
e
e
1
1
5
5
C
C
O
O
2
2
O
O
u
u
t
t
p
p
u
u
t
t
s
s
Gas Type
Natural
LPG
Injector Dia. Min
None
5.7mm
Wo (MJ/m3)
15.0
24.3
CO
2
% partial
load
9.0 – 9.5
11.5 –
12.0
CO
2
% full load
8.5 – 8.8
15.5 –
11.0
C0 ppm partial
load
<15 <20
C0 ppm full load
<50
<150
The measured CO
2
and Co values are for
partial load (20%) and full load (100%) with
the casing removed.
When the setting is correct press the flue
emissions test button once and the boiler
will revert to normal operation.
31.1
Flue System Check
In order to examine the flue pipe sealing it is
essential that an O
2
or CO
2
reading is taken
from the 8mm plastic pipe that should be
positioned from the Grey Vent/Flue adapter
led down and through the bottom boiler
plate.
The flue seal is satisfactory when the CO
2
value is no more than 0.2% and the O
2
value no more than 20.6%
31.2
STB Test Button (Green).
This button is used to test the correct
operation of the overheat thermostat (high
limit thermostat).
32. Diagnostics
32.1
Control panel
The control panel of the unit has a LCD
screen displaying two lines of data. This
screen provides information about the
operation of the boiler it displays operation
messages (non-flashing) and fault
messages (flashing display).
The first line contains textual information on
the operating status of the unit. It shows:
EC 16~38 Installation Manual page
49
