KROHNE H250 M40 ATEX II2D Ex t-II2G Ex d EN - Manual (Page 18)

6
SERVICE
18
H250 M40
www.krohne.com 07/2012 - 4002069601 - MA H250/M40-Ex-II2GD-AD R01
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
General notes
Removal and installation are the responsibility of the operator.
Due to the modular structure of the variable area flowmeters, from a safety point of view it is
possible to exchange complete indicators or their components for identical spare parts.
Only identical indicators or modules from the manufacturer may be used.
If it is absolutely necessary to open the flameproof enclosure or the dustproof electronics
compartment in the presence of a potentially explosive atmosphere, the device must be de-
energised.
Before connecting or disconnecting the electrical connection cables of the device, make sure
that all cables leading to the converter are isolated from the ground of the hazardous area. This
also applies to protective earth (PE) or functional earth (FE) and equipotential bonding
conductors (PA).
After opening the converter, grease the converter's flashback resistant cover threads including
the cover seals if necessary. Use the multi-purpose grease NONTRIBOS
® , type Li EP2.
Replacing the indicator / modules
When exchanging a complete indicator or individual modules, refer to the section "Connecting
power and I/O functions". In both cases, the measuring tube of the variable area flowmeter can
remain in the pipeline. This also applies to line systems carrying product.
WARNING!
CAUTION!
There may be a loss of measuring accuracy!
Faulty prisms between the measuring tube and the display housing should be replaced.
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