Keston C45 Installation And Servicing Instructions page 31

WD536 Chapter 4 : Commissioning
LESS THAN THE CO2 LEVEL AT HIGH RATE. ADJUSTMENTS, IF MADE, SHOULD BE
IN STEPS OF NO MORE THAN 1/8 OF A TURN. YOU MUST WAIT 1 MINUTE AFTER
EACH ADJUSTMENT TO ALLOW THE SETTING TO STABILISE BEFORE TAKING A
READING
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.
4.8 CHECKING THE GAS PRESSURE
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
soundness 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
4.9 Timing The Gas Meter. If the gas input cannot be measured then it's
compulsory to measure the combustion quality as detail in Section 4.7 Combustion
Testing.
4.9 TIMING THE GAS METER
After the boiler has been started, and with no other appliances using gas, time the gas
meter to be certain that the unit is running at the proper gas input. Determine the cubic
feet of gas passing through the meter and determine the input in Btu per hour. Input must
be within plus or minus 5% of the rated input.
Time, in seconds, the time taken to pass 2 cubic feet of gas through the meter (i.e. one
revolution of a 2 cu ft dial) or 0.1 cubic metres if the meter is of the new metric digital type.
Model
C45 (natural gas)
C40P (LPG)
C55 (natural gas)
C55P (LPG)
If the meter timing is found to be incorrect when the boiler is firing at maximum rate
contact Keston Boilers Ltd for further guidance.
Installation & Servicing Instructions
The Keston C45, C40P, C55 & C55P
Time for 2 cu ft
48
125
39
105
Time for 0.1 cu m
85
221
68
185
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