Checking The Gas Pressure - Keston Qudos 28s User, Installation And Servicing Instructions

WD420/3/2007
1) Set any controls to call for
heat.
2) Press
repeatedly until the display
shows "SEr",
"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
the flue gases and adjust, if
necessary,
screw (pos 4) to produce a
CO reading of 8.9% to 9.3% with a corresponding CO level of 50 to 150 ppm for
2
natural gas and 10.3 to 10.7% with a corresponding CO level of 50 to 150 ppm for
LPG. NORMAL ADJUSTMENT, IF REQUIRED, 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
8.8% with a 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,
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.
5.8

CHECKING THE GAS PRESSURE

With the boiler running measure the burner pressure at the burner pressure test nipple.
(pos. 4).
NB: It is advisable to carry out this test with the thermostat set to maximum and the system
water cold to ensure the boiler is running at maximum rate.
The gas setting is factory adjusted to within the required range and should not need
adjustment. If the reading is incorrect then check such factors as tightness of the air and
flue pipe joints and the gas inlet pressure (pos. 3) (minimum 18 mbar required for natural
gas, minimum 31 mbar required for LP gas).
If all joints are sound and the gas inlet pressure is satisfactory check the gas input
by timing the gas meter as detail in Section 5.9 Timing The Gas Meter. If the gas
input cannot be measured then it's compulsory to measure the combustion quality
as detail in Section 5.7 Combustion Testing.
Installation & Servicing Instructions
Chapter 5 : Commissioning
the " " button
then press
reading in
2
the adjustment
reading in the flue gases. The CO
2
the process again from step 3.
The Keston Qudos 28s & Qudos 28sP Boilers
reading must be 8.4% to
2
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