VAG Operation and Maintenance Instructions • 14
For valves used in gas applications the use of suitable grease is
mandatory.
8 Trouble-shooting
For all repair and maintenance work, please observe the general
safety instructions described in Section 7.1!
9 How to contact us
Head office
VAG GmbH
Carl-Reuther-Str. 1
68305 Mannheim
Germany
Phone: +49 (621) 749-0
Fax: +49 (621) 749-2153
info@vag-group.com
http://www.vag-group.com
Service
Our service hotline can be reached 24/7 world-wide. In case of
emergency, please contact us by phone.
Service hotline: +49 621 - 749 2222
Service by E-Mail: service@vag-group.com
Problem
Cause
Remedial action
Valve makes noise
Unfavourable installation position
causing unfavourable flow around
or inside the valve (e.g. installed too
closely downstream of an elbow etc.)
Change installation position
Valve operating be-
yond its design limits
Check design and/or operation data, change flow resist-
ance in the valve, if required, by using different internals
Valve cannot be operated
Foreign matter jammed in the seat area Flush valve, dismantle, if necessary, and remove foreign matter
Gear blocked
Undo block
No electrical connec-
tion of electric actuator
Establish electrical connection
Unfavourable flow and im-
pairment of movement
Change installation position
Leaks in the body seat
Valve not completely closed yet
Close valve completely
Valve seal damaged or worn
Replace seal
Cavitation in valve
Valve operating beyond its design limits Butterfly valve not suitable for use as control valve. Replace valve by a
more suitable valve type.
Operational data changed
Leaks at the body
Deterioration of seals
Replace seals or collar
High operating forces
Seat of the valve polluted by deposits
Flush valve, dismantle, if necessary, and clean seat area
Valve is dry in pipeline, no medium
present
Valve can be operated more easily when wet
