KROHNE H250 M40 ATEX II3G Ex nA EN - Manual (Page 19)

SERVICE
6
19
H250 M40
www.krohne.com 01/2012 - 4001485201- MA H250/M40-Ex-II3G-AD 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.
To maintain proper condition, regular inspections are required for systems in hazardous areas.
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.
• Including the flowmeter in the regular pressure test of the process line.
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 so, 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.
Exchanging the entire device
Removal and installation are the responsibility of the operator.
Before disconnecting the electric connecting cable of the device, make sure that all cables
leading to the indication unit are isolated from the ground of the hazardous area. This also
applies to functional earthing conductors (FE) and equipotential bonding conductors (PA).
CAUTION!
There may be a loss of measuring accuracy!
WARNING!
•
Pressurized pipes have to be depressurized before removing the measuring unit.
• In the case of environmentally critical or hazardous products, appropriate safety precautions
must be taken with regard to residual liquids in the measuring unit.
• New gaskets have to be used when re-installing the device in the piping.
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