Keston Qudos 28s User, Installation And Servicing Instructions page 67

2) Press the " " button repeatedly until the
display shows "SEr", then press "ENTER". Press
the " " until the display shows "100%". Press
"ENTER" and the boiler will be locked on at
Maximum rate. If no further buttons are pressed
for 10 minutes the boiler will automatically revert
to normal operation.
3) Measure the CO
gases and adjust, if necessary, the adjustment
screw (pos 4) to produce a CO
9.3% with a corresponding CO level of 50 - 150
ppm for natural gas and 10.3 - 10.7% with a
corresponding CO level of 50 - 150 ppm for LPG.
NORMAL ADJUSTMENT,
SHOULD NEED NO MORE THAN HALF OF ONE
ROTATION OF THE ADJUSTMENT SCREW
(pos. 4).
4) Press the "RESET" button once and then
press the "ENTER" button. Use the " " button
until the display shows "32%" ("30%" for LPG).
Press the "ENTER" button and the boiler will be locked on at Minimum rate. If no further buttons are pressed
for 10 minutes the boiler will automatically revert to normal operation.
5) Measure the CO
corresponding CO level of 5 to 20 ppm for natural gas and 9.5% to 9.9% 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.
6) Press the "RESET" button once and then use the " " button until the display shows "100%". Press
the "ENTER" button and the boiler will be locked on at Maximum rate. Check the setting is within the range
established in step 3. If not, repeat the process again from step 3.
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)
8) Press the "RESET" button twice to return to the normal operation mode and display.
reading in the flue
2
reading of 8.9% -
2
IF REQUIRED,
reading in the flue gases. The CO
2
reading must be 8.4% to 8.8% with a
2
2/2
WD478/0/2008