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Commissioning must not take place outside of the permissible pressure
range.
▶ Identify the cause and rectify the fault.
▶ If this is not possible: isolate the device on the gas side and notify the
gas supplier.
▶ Exit the chimney sweep mode.
▶ Switch off the device, close the gas isolator, remove the pressure
gauge and tighten the screw.
▶ Refit the casing.
Gas pressure within the system
The appliance must be running at maximum output rate when
performing the gas rate check, ( chapter 6.4.1).
Combi appliances
▶ Running a hot water tap does not guarantee the appliance will
operate at maximum output throughout the test.
Refer to the figures below for Natural Gas gas pressures.
The pressure drop from the natural gas meter to the gas valve inlet test
point must not be more than the values stated in table 25.
If the pressure drops are greater than shown in table 25, then this would
indicate a problem with the pipe work or connections within the system.
NOTICE
Do not continue commissioning until the correct gas pressure is
achieved with the appliance running at maximum output.
Gas
Meter
Across
Type
pipe
work
Allowed mbar pressure drop
NG
20
1
Table 25 Allowed mbar pressure drop
Gas supply pressure drop
Natural Gas
Meter
18.5 - 23 mbar
Appliance inlet
1.0 mbar
drop
17.5 - 22 mbar
Fig. 67 Natural Gas pressures
[A]
Pressure loss across the appliance
[B]
Pressure reading at inlet test point
Greenstar 1000 – 6721835943 (2023/08)
Appliance
Across
Gas valve
inlet
appliance
inlet test
[A]
point [B]
17.5 - 22
0.5
17 - 21.5
mbar range
Gas Control
valve
Inlet test point [B]
16.0 - 20.5 mbar
0010048738-002
6.6
Checking the gas rate
▶ The gas rate should be measured at the gas meter after the appliance
has been operating for a minimum of 10 minutes at maximum output.
▶ Where a gas meter is not available the CO/CO
▶ Refer to Technical data section of this manual for the appliance gas
rates and CO/CO
ratios.
2
▶ Gas rate must be checked with the appliance in service, maximum
output test mode.
▶ Carry out Gas rating procedures as described in current standards.
▶ Ensure all other gas appliances are isolated when carrying out the gas
rate check on the appliance.
▶ Ensure all other gas appliances are isolated.
▶ Press the ok button until the C symbol appears on the display.
The display shows the maximum percentage of the power 100%
alternating with the flow temperature.
▶ Ensure that the appliance has stabilised at maximum output.
▶ If pressure and gas rate are satisfactory press the ok button and the
appliance will return to normal operation.
– If left in the service mode the control will return to normal
operation after 30 minutes.
▶ Close the gas isolation valve.
▶ Remove the manometer.
▶ Re-seal the screw in the gas inlet pressure test point.
▶ Open the gas isolation valve.
▶ Ensure that there are no gas leaks.
6.7
Checking for gas leaks during operation
▶ Use an approved gas sniffer or leak detection fluid to check all
connections for possible leaks. Leak detection fluid must be certified
as a gas leak testing agent.
▶ Do not allow leak detection fluid to come into contact with the
electrical components.
6.8
CO and combustion check
The following combustion and flue integrity checks are mandatory and
these values must be recorded on the Benchmark check list, at the end
of these instructions.
Once the gas rate and pressure have been confirmed as acceptable then
the CO and combustion checks can be undertaken.
The flow chart is given for guidance, the details of the checks are given in
the following sections:
• Checking flue integrity ( chapter 6.9).
• Flue gas analysis ( chapter 6.10).
NOTICE
Before CO and combustion checks:
▶ Verify the appliance is connected to the correct gas type.
▶ Ensure the appliance is supplied with the correct gas inlet pressure
and gas rate as specified previously in the Commissioning section.
▶ Visually check the integrity of the whole flue system and confirm that
all the components are correctly assembled, fixed and supported.
▶ The flue gas analyser must be the correct type as specified in BS
7967. Before use the analyser must have been calibrated as
specified by the manufacturer. The installer must be competent in the
use of the analyser.
▶ Check and zero the analyser in fresh air as specified by the
manufacturer.
▶ The air/gas ratio valve is factory set and must not be adjusted during
commissioning unless this action is recommended following contact
with the Worcester, Bosch Group help line 0330 123 3366.
Commissioning
must be checked.
2
45
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