4.16 Gas/Air Valve Setup Procedure
C
hec
k
ing the
C
O
2
1
. The combustion (
C
O
2
) may be chec
k
ed at maximum
rate using a suitably calibrated analyser after running
the boiler for several minutes.
2. To do this it is necessary to set the boiler to
C
alibration Mode.
3. Ensure that all external controls are calling for heat.
The actual current boiler temperature is shown on the
display.
4. Turn both temperature control
k
nobs fully
anticloc
k
wise, then quic
k
ly turn the DHW temperature
k
nob
1
/
4
cloc
k
wise twice and bac
k
fully anticloc
k
wise.
5
. The display will now alternate between SF and the
current boiler temperature and both green
L
EDs will
flash.
6. Turn the
C
H temperature
k
nob fully cloc
k
wise. As
the
k
nob is turned the display will change, indicating
the percentage of maximum fan speed.
7
. The display will show 00, indicating maximum rate,
then revert to
P
alternating with the current boiler
temperature.
8
. Remove the plug from the flue adaptor test point.
Insert the analyser probe and allow time for the
reading to settle.
The
C
O
2
should be
8
.9% ± 0.2
9. It is possible to alter the
C
O
2
by adjustment of the
gas valve. At maximum rate the Max. Rate throttle
adjustment screw should be turned cloc
k
wise to
decrease
C
O
2
, anti-cloc
k
wise to increase
C
O
2
using a
suitable 2.
5
mm hexagon
k
ey, until the correct reading
is obtained.
1
0. The
C
O
2
must then be chec
k
ed at minimum rate.
Turn the
C
H temperature
k
nob fully anticloc
k
wise. As
the
k
nob is turned the display will change, indicating
the fan speed. When the display reads 0 the boiler
runs at minimum rate.
The
C
O
2
should be
8
.6% ± 0.2.
11
. If at minimum
C
O
2
is not correct please ring our
after sales service department.
1
2. The
C
alibration Function is maintained for 20
minutes unless the maximum
C
H temperature is
exceeded. The function can be disabled at any time by
turning the DHW
k
nob.
MAX0031B
Air/Gas
Ratio Valve
Top View
I
nlet
Pressure
Test
Point
Outlet
Pressure
Test
Point
S
ignal
sensing
tube
connected
to
Fan
Air
S
ignal
Connection
Offset
Ad
j
ustment
Throttle
Ad
j
ustment
Flue Adaptor
Test
P
oint
Min Gas Rate
Max Gas Rate
Burner
P
ressure
(mb)
0.6 - 0.
8
6.
8
-
7
.2
Gas
Rate
(m
3
/hr)
0.
7
- 0.
7
4
2.4
8
- 2.
7
4
C
O
(ppm)
2 - 30
30 -
1
00
C
O
2
(%)
8
.4 -
8
.
8
8
.
7
- 9.2
44
© Baxi Heating UK Ltd 2015