Checking Gas Inlet Pressure; Measuring The Inlet Pressure; Checking The Gas Rate - Worcester Greenstar FS 30CDi Installation, Commissioning And Servicing Instructions

5.5

Checking gas inlet pressure

5.5.1

Measuring the inlet pressure

The inlet pressure to the appliance must be checked using the following
procedure:
1
Fig. 35 Inlet test point
Close the gas isolation valve.
Slacken the screw in the inlet pressure test point [1] and connect a
manometer.
Open the gas isolation valve.
Measure the pressure with the boiler running at maximum.
– Press Service engineer button [8] for more than ten seconds and
set Central Heating temperature to maximum.
– The Service engineer button [8] will illuminate continually and the
blue power indicator will pulse five times.
Check the gas supply working pressure at the gas valve conforms to
values shown in figure 36 or figure 37.
Ensure inlet pressure is satisfactory with all other gas
appliances working.
Gas pressure within the system
The boiler must be running at maximum output rate
when performing the gas rate check.
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 for Natural Gas
• 2.5 mbar for L.P.G.
The pressure drop from the meter to the gas valve must not be more
than:
• 2.5 mbar for Natural Gas
• 4 mbar for L.P.G.
If the pressure drops are greater than shown below, then this would
indicate a problem with the pipe work or connections within the system.
ErP
Greenstar FS CDi 6720818079 (2016/04)
Meter
Natural Gas
< 2.5mbar
difference
19 - 23 mbar
Boiler inlet
1 mbar
drop
18 - 22 mbar
Fig. 36 Natural gas pressures
[≤ ] Equal to or less than
Regulator
L.P.G.
< 4.0mbar
difference
32 - 45 mbar
Boiler inlet
2.5 mbar
drop
29.5 - 42.5 mbar
Fig. 37 L.P.G. pressures
NOTICE: Gas pressure
Do not continue commissioning until the correct gas
pressure is achieved.
If pressure is satisfactory press the Service engineer button [8] again
and the boiler will return to normal operation.
If left in the Service mode the control will return to normal operation
after 15 minutes.
Re-seal the screw in the gas inlet pressure test point.
5.5.2

Checking the gas rate

The gas rate should be measured at the gas meter after 10 minutes
operation at maximum, refer to technical data in section 2.2.
Where a gas meter is not available (e.g. LPG) the CO/CO
checked to the units shown in the setting the air/gas ratio,
refer to section 6.8.
If pressure and gas rate are satisfactory press the Service engineer
button [8] again and the boiler will return to normal operation.
– If left in the service mode the control will return to normal
operation after 15 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.
Replace the outer case.
COMMISSIONING
Gas Control
valve
16.5 - 20.5 mbar
1.5 mbar
drop
6 720 815 062-44.1O
Gas Control
valve
28 - 41 mbar
1.5 mbar
drop
6 720 815 062-45.1O
must be
2
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