Commissioning; Checking The Gas Inlet Pressure - Worcester GREENSTAR 24i Junior Installation Instructions Manual

COMMISSIONING

5.6 COMMISSIONING
NOTICE: The combustion settings on this
gas-fired boiler have been checked, adjusted
and preset at the factory for operation on the
gas type defined on the data plate.
No measurement of the combustion values
are necessary provided there is a meter
installed allowing the gas rate to be checked.
DO NOT ADJUST THE AIR/GAS RATIO VALVE.
When running in the service mode, the boiler
will operate both the central heating and the
domestic hot water circuits. This is to allow
sufficient time for this part of the
commissioning procedure. It will be
necessary to run water through the domestic
hot water circuit to ensure that the boiler will
not cycle on low heating demands.
Having checked:
B That the boiler has been installed in accordance with
the installation instructions.
B The integrity of the flue system and flue seals, as
described in section 6.3 of this manual.
B The integrity of the boiler combustion circuit and
relevant seals.
5.6.1

CHECKING THE GAS INLET PRESSURE

The inlet pressure to the appliance must be checked
using the following procedure:
MEASURING THE INLET PRESSURE
1
Fig. 62 Inlet pressure test point
B Close gas isolation valve.
B Slacken the screw in the inlet pressure test point (1)
and connect a manometer.
B Open gas isolation valve.
B Measure the pressure with the boiler running at
maximum.
– Press service button for more than ten seconds
and set Central Heating temperature to maximum.
– The service button will lit continually and the blue
power indicator will pulse five times, quickly.
B Check the gas supply working pressure at the gas
valve inlet point is no less than:
40
GAS PRESSURE WITHIN THE SYSTEM
Refer to the figures below for natural gas or L.P.G gas
pressures.
The pressure at the boiler must not be less than the
pressure read at the meter minus 1 mbar.
The pressure drop from the meter to the gas valve must
not be more than 2.5 mbar. The pressure at the gas valve
must not be less than the pressure read at the meter
minus 2.5 mbar.
If the pressure drops are greater than shown below,
then this would indicate a problem with the pipe work or
connections within the system.
Fig. 63 Natural gas pressures
6720643895-53.1Wo
Fig. 64 L.P.G. pressures
Ensure inlet pressure is satisfactory with all
other gas appliances working.
Meter
Natural Gas
19 - 23 mbar
Boiler inlet
1 mbar
drop
18 - 22 mbar
Regulator
L.P.G.
32 - 45 mbar
Boiler inlet
2.5 mbar
drop
29.5 - 42.5 mbar
NOTICE:
Do not continue commissioning until the
correct gas pressure is achieved.
6 720 644 741a (2010/10)
Gas Control
valve
16.5 - 20.5 mbar
1.5 mbar
drop
6720644744-44.1Wo
Gas Control
valve
28 - 41 mbar
1.5 mbar
drop
6720644744-45.1Wo