38
11.6 Gas Rate
The gas valve is factory set for natural gas (G20) and should
need no adjustment.
Should any doubt exist about the gas rate, check it using the
gas meter test dial and stop watch, at least 10 minutes after
the burner has lit, see diagram 11.3 for approximate rates.
Make sure that all other gas burning appliances and pilot
lights are off.
It should be noted that the appliance will modulate the heat
input according to demand. This may affect the gas rates
measured if the appliance reaches its operating temperature
during the measurement.
Adjusting the gas valve requires a combustion analyser and
should only be carried out by a competent person, but in
the unlikely event that the gas valve needs adjusting, refer to
section 12.7.
Flue Gases: If any doubt exists that the flue products are
not exhausting correctly, investigate by use of a flue gas
analyser (FGA).
NOTE: The burner pressure cannot be meas-
ured at the gas valve as it is altered by the
suction of the fan and modulated according to
demand.
11.7 Heating System
Check that all external controls are calling for heat. The
boiler will fire automatically. Fully open all radiator valves,
flow control valve ‘A’ and bypass valve ‘B’, see diagram 5.3.
Balance the radiators as required and if fitted adjust valve ‘A’
to give the required system differential. Turn off all radiators
that can be shut off by the user and check to see if less than
the maximum differential allowed of 20
O
C can be achieved
across flow and return.
Allow the system to reach maximum temperature then switch
off the boiler by isolating from the electrical supply.
The pump overrun will continue for 5 mins.
Drain the entire system rapidly whilst hot, using the drain taps
at all the low points of the system. Fill and vent the system as
described previously.
Lock or remove the handle from control valve ‘A’ to prevent
unauthorised adjustment.
11.8 Completion
Fit the base coverplate, see diagram 11.4.
Ensure that the magnetic lighting instruction label is placed
on the surface of the boiler casing
GB: It is a requirement that the “Benchmark” Installation,
Commissioning and Service Record is completed and left
with the user.
IE: it is necessary to complete a “Declaration of Conformity”
to indicate compliance to I.S.813. An example of this is given
in the current edition of I.S.813.
11.9 Instruct the User
Demonstrate, then instruct the User about the lighting
procedure and heating system controls operation.
Advise that to ensure the continued efficient and safe
operation of the boiler it is recommended that it is checked
and serviced at regular intervals. The frequency of servicing
will depend upon the installation conditions and usage, but in
general, once a year should be enough.
11 Commissioning
Diagram 11.4
13540
Draw attention, if applicable, to the current issue of the
Gas Safety (Installation and Use) Regulations, Section 35,
which imposes a duty of care on all persons who let out any
property containing a gas appliance in the UK.
The user shall not interfere with or adjust sealed components.
It is the Law that any servicing is carried out by a competent
person.
Advise the user that, like all condensing boilers this appliance
will produce a plume of condensation from the flue terminal in
cool weather. This is due to the high efficiency and hence low
flue gas temperature of the boiler.
Advise the user of the precautions necessary to prevent
damage to the system, boiler and the building, in the event of
the heating system being out of use during frost or freezing
conditions.
Advise the user that the permanent mains electrical supply
SHOULD NOT be switched off, as the built in frost protection
and pump saver program will not operate.
Advise the User if the mains electricity and gas are to be
turned off for any long periods during severe weather, it is
recommended that the whole system, including the boiler,
should be drained to avoid the risk of freezing.
NOTE Sealed System: Contact your installation/servicing
company as draining, refilling and pressurising MUST be
carried out by a competent person.
Leave these instructions and the ‘Benchmark’ Installation,
Commissioning and Service Record with the user.
Diagram 11.3
13862
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