Setting The Gas Valve - Baxi Bermuda BBU 15 HE Installation & Servicing Instructions Manual

Flue Sampling
Point
Display
Control
Knobs
Fig. 57
Fig. 59
Fig. 60
Min Rate
Adjustment Screw
(cap fitted)
Reduce CO Increase CO
2 2
at min. rate at min. rate
If the CO
be rechecked at maximum rate again and
adjusted if required. If the CO
maximum rate it must be rechecked at
minimum rate and adjusted if required.
© Baxi Heating UK Ltd 2009
Fig. 56
Fig. 58
Fig. 61
Reduce CO
at max. rate
Fig. 62
is reset at minimum rate it must
2
is reset at
2

11.0 Setting the Gas Valve

11.1
IMPORTANT: The CO
adjusted to set the valve if a suitable calibrated
combustion analyser is available, operated by a
competent person - see Section 9.1
1. The combustion (CO
boiler for several minutes. To do this it is necessary to set
the boiler to 'Calibration Mode'.
2. Ensure that all external controls are calling for heat. The
actual current boiler temperature is shown on the display.
3. Turn both control knobs fully anticlockwise, then quickly
turn the right hand knob
anticlockwise (Fig. 56).
4. The display will now alternate between 'SF' and the
current boiler temperature and both green LEDs will flash
(Figs. 57 & 58).
5. Turn the left hand knob fully clockwise. As the knob is
turned the display will change, indicating the fan speed.
6. The display will show '00', indicating maximum rate, then
revert to 'P ' alternating with the current boiler temperature
(Figs. 59, 60 & 61 ).
7. Remove the plug from the flue sampling test point. Insert
the analyser probe and allow sufficient time for the reading
to settle (Fig. 56).
8. It is possible to alter the CO
valve. Remove the plastic cover from the 'Max Rate'
adjustment screw. At maximum rate the 'Max. Rate'
adjustment screw should be turned, using a suitable hexagon
key, until the correct reading is obtained (Fig. 62).
Turning clockwise will reduce the CO
increase the CO
Max Rate
Adjustment Screw
(cover removed) 9. The CO
the left hand knob fully anti-clockwise. As the knob is turned
the display will change, indicating the fan speed. When the
display reads ' 0' the boiler runs at minimum rate.
Increase CO
2 2
at max. rate
10. With the boiler on minimum, the 'Min. Rate' adjustment
screw must be altered, using a suitable hexagon key, after
removing the cap (Fig. 62). Turning anti-clockwise will reduce
the CO
11. The 'Calibration Function' is maintained for 20 minutes
unless the maximum CH temperature is exceeded. The
function can be disabled at any time by turning the right
hand knob.
12. Check the CO/CO
Setting the Gas Valve ( CO
2
must be only be checked and
2
) may be checked after running the
2
1 / clockwise twice and back fully
4
The CO should be 9.3% ± 0.2
2
by adjustment of the gas
2
. Anticlockwise will
2
.
2
must then be checked at minimum rate. Turn
2
The CO should be 8.2% ± 0.2
2
. Clockwise will increase the CO
2
ratio. This must be less than 0.004.
2
check)
.
2
33