Keston C40 Installation And Servicing Instructions page 55

When firing the boiler for the first time since installation, the CO level at high rate may be
between 100-220 ppm and between 50-80 ppm at low rate. This is due to compounds used
during manufacture curing within the combustion chamber. On boilers which have been fired
for more than one hour since installation, the CO levels should not exceed 150 ppm at high
rate and 50 ppm at low rate. If CO levels above these values are experienced, the combustion
chamber and flue system should be investigated.
Check combustion errors are not a result of incorrectly installed flue and/or air system,
terminal location or damage or debris on the burner. If all these factors are found to be in
order precede as follows:
1) Set any controls to call for heat.
2) Set the boiler to run at maximum /
minimum fan speed. To do this is necessary
to access the hidden buttons (behind the
"KESTON" label under the display). There are
five buttons, which are used to adjust settings
and provide additional boiler information. The
drawing below shows the layout of these
buttons and their function.
To set the fan to maximum.
Press the "Mode" button
repeatedly until the display
shows "Stby". Press and hold the
"Mode" and "+" key together for 2
seconds. The display will then show
"H nn". The unit is now locked on max fan speed.
3) Measure the CO
screw (pos. 5) to produce a CO
to 150 ppm. NORMAL ADJUSTMENT, IF REQUIRED, SHOULD NEED NO MORE THAN
HALF OF ONE ROTATION OF THE ADJUSTMENT SCREW (pos. 5).
To set the fan to minimum
Press the "Mode" button repeatedly until the display shows "Stby". Press and hold the
"Mode" and "-" keys together for 2 seconds. The display will then show "L nn". The
unit is now locked on min fan speed.
4) Measure the CO
with a corresponding CO level of 5 to 20 ppm for LPG. THE CO2 LEVEL AT LOW RATE
MUST ALWAYS BE LESS THAN THE CO2 LEVEL AT HIGH RATE.
If following the above procedure, combustion levels described above at both high and
low rate could not be obtained, please turn off the appliance and isolate the gas to the
appliance. Telephone KESTON BOILERS technical support (phone no. 0208 462 0262)
To revert to normal modulation
Press the "Mode" button repeatedly until the display shows "Stby". Press and hold the "+" and
"-" keys together for 2 seconds.
vi) Note the original appliance serial number band production date on the new data badge
vii) Stick the new data badge C.13.1.00.02.0 ( for the C40P - Fig. 6.7.4 item 3) into the appliance
in place of the original NG data badge.
viii) Reassemble (Section 7.3).
Supply pressure:
reading in the flue gases and adjust, if necessary, the adjustment
2
reading of 8.2% to 8.7% with a corresponding CO level of 50
2
reading in the flue gases. The CO
2
Keston Condensing Boilers NG Specifications
High 25 mbar
Normal 20 mbar
Low 17 mbar
WD326/1/2008
reading must be 8% to 8.2%
2
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