• Close the upstream valve .
• Slowly open the small bleed valve V2 . The pres-
sure variation should not exceed 0 . 3 bar per
second .
• Some gas still inside the meter and the pipe,
therefore sufficient ventilation is required .
5.4 Meters placed after a regulator
Installation has to be done in accordance with the
technical manual of the specific regulator . During
pressurisation and depressurisation, insure that
the pressure variation should not exceed 0 . 3 bar
per second .
6 Maintenance
6.1 Maintenance of the meter
Once installed, the meter does not require any
specific attention except a periodical check or
change of the lubricant filled in the covers .
After start-up:
Natural gas: After the preliminary term of service,
the lubricant level should be checked .
Other gases: After a working period of 100 hours
from commissioning, the lubricant level should be
checked .
If the lubricant level is appreciably low, if the lubri-
cant is emulsified or if there is a chemical reaction
between the lubricant and the gas, the lubricant
should be reassessed and changed to fit the pre-
vailing conditions .
Periodical change of lubricant:
The period between checks or changes of lubri-
cant depends of the operating conditions (pres-
sure variation, flow rate . . . ) .
Natural gas: Under normal conditions, lubricant
has to be changed every 5 to 8 years . When the
meter is used with extremely clean gas the period
can be extended .
Other gases: Please consult us .
Use solvent and alcohol free product to clean the
meter .
Repair must be done only by qualified personal .
Afterwards a tightness test with 1 . 1 x PS (Pmax)
must be performed .
If used with wet gas, internal and external effect of
corrosion has to be checked regularly and in case
of severe corrosion, the meter has to be replaced .
Spare parts:
When changing pressure containing parts, ensure
that spare parts that comply with the PED are
used .
The right spare parts are traced by providing the
serial number of the meter to Itron and/or by us-
ing the Itron CD ROM "Spare parts catalogue" .
6.2 Maintenance of optional
equipment
6.2.1 LF and HF transmitters
These transmitters do not require any specific
maintenance . The function of the transmitters can
be checked by comparing the electronic index
with the meter index .
6.2.2 Filter
If an increase of pressure loss is noticed, the filter
should be checked and cleaned/replaced before
any maintenance on the meter .
7