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WD420/3/2007
7)
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.
5.9
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
Qudos 28s (natural gas)
Qudos 28sP (LPG)
If the meter timing is found to be incorrect when the boiler is firing at maximum rate
contact KESTON Heating for further guidance.
5.10
HANDING OVER TO THE USER
It is important to fully explain the following:
a.
Procedure to light and turn off the boiler, including isolation of the electrical supply
if necessary.
b.
The function of the lockout feature must be explained :
If the display shows "E 02" this means that the boiler has failed to light. Press the
"Reset" button and wait
i)
ii)
c.
Advise that a reduction in the water pressure reading on the system pressure
gauge, for sealed systems, indicates a leak which should be rectified before
further use.
d.
Advise that the appliance must be serviced by a competent person at least once a
year.
Complete all sections of the Chapter 10 Gas Boiler Commissioning Checklist that are
relevant to the appliance installation. The details will be required in the event of any
warranty work.
e.
Advise on the frost protection and pump/fan exercise feature.
f.
Advise the user that a plume of water vapour (steam) from the flue terminal is
normal and that there is no need for concern.
Installation & Servicing Instructions
Chapter 5 : Commissioning
Time for 2 cu ft
71 to 78 seconds
152 to 168 seconds
If lockout recurs immediately then the gas supply should be checked as
ON, otherwise consult a Service Engineer.
If it is not possible to relight, the boiler must be isolated and a Service
Engineer called in to rectify the fault.
The Keston Qudos 28s & Qudos 28sP Boilers
Time for 0.1 cu m
125 to 138 seconds
272 to 300 seconds
Page : 30
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