Checking The Gas Rate; Checking For Gas Leaks During Operation - Worcester Greenstar 2000 Installation And Maintenance Instructions Manual

Gas pressure within the system
The appliance must be running at maximum output rate when
performing the gas rate check, ( chapter 6.5.1).
Combi appliances
▶ Running a hot water tap does not guarantee the boiler will operate at
maximum output throughout the test.
Refer to the figures below for Natural Gas and LPG gas pressures.
The pressure drop from the natural gas meter or LPG storage tank to the
gas valve inlet test point must not be more than the values stated in table
24.
If the pressure drops are greater than shown in table 24, 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.
Gas Meter Across
Type pipe
work
Allowed mbar pressure drop
NG 19 - 23 1
LPG 32 - 45 2.5
Table 24 Allowed mbar pressure drop
Gas supply pressure drop
Natural Gas
Meter
19 - 23 mbar
Appliance inlet
1.0 mbar
drop
18 - 22 mbar
Fig. 64 Natural Gas pressures
[A] Pressure loss across the appliance
[B] Pressure reading at inlet test point
Gas supply pressure drop - LPG
Greenstar 2000 – 6 721 820 552 (2021/02)
Appliance Across Gas valve
inlet appliance inlet test
[A] point [B]
18 - 22 1.5 16.5 - 20.5
29.5 - 42.5 1.5 28 - 41
mbar range
Gas Control
valve
Inlet test point [B]
Across appliance
drop [A]
0010012820-001
LPG Storage
32 - 45 mbar
0.5 mbar drop
Regulator
Appliance inlet
2.5 mbar
drop
29.5 - 42.5 mbar
Fig. 65 LPG pressures
[A] Pressure loss across the appliance
[B] Pressure reading at inlet test point
6.7

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 (e.g. LPG) the CO/CO2 must be
checked.
▶ 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.
Maximum output mode
▶ A hot water outlet can be opened to prevent the appliance from
shutting down due to high temperature during testing.
▶ 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.
6.8

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.
Commissioning
LPG
Gas Control
valve
Inlet test point [B]
Across appliance
drop [A]
0010036553-001
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