KROHNE H250 M9 NEPSI Ex nA - Manual (Page 15)

SERVICE
6
15
H250 M9
www.krohne.com 03/2013 - 4002616501 AD H250 M9 NEPSI Ex nA R01 en
Service
6.1 Maintenance
Maintenance work of a safety-relevant nature within the meaning of explosion protection may
only be carried out by the manufacturer, his authorised representative or under the supervision
of authorised inspectors.
For systems in hazardous areas, regular tests are required in order to maintain the proper
condition.
The following checks are recommended:
• Checking the housing, the cable entries and the feed lines for corrosion and/or damage.
• Checking the measuring unit and the piping connections for leakage.
• Checking the measuring unit and the indicator for dust deposits.
6.2 Dismantling
Exchanging the built-in equipment
Due to the modular structure of the variable area flowmeters, from a safety point of view it is
possible to exchange the electrical equipment built into the indicator for identical spare parts.
To do this, remove the housing cover. The housing cover must be closed immediately after the
spare parts are exchanged. Make sure that the cover seal is properly seated. The fastening
screws of the housing cover should be tightened with a torque of 1.2 Nm.
Exchanging the entire device
Removal and installation is the user's responsibility.
Before disconnecting the electric connecting cable of the device, it must be ensured that all of
the cables leading to the indicator part are de-energised relative to each other and to the
reference potential of the hazardous area. This also applies to functional earthing conductors
(FE) and equipotential bonding conductors (PA).
CAUTION!
Avoid electrostatic charges when cleaning the sight window!
CAUTION!
There may be a loss of measuring accuracy!
CAUTION!
•
Pressurized pipes must be depressurized before removing the measuring section.
• In the case of environmentally critical or hazardous products, appropriate safety precautions
must be taken with regard to residual liquids in the measuring section.
• New seals must be used when re-installing the device in the piping.
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