Malfunctions
34
Operating Instructions · VARIVENT
®
Mixproof Valve L with Lifting Actuator, suitable for pigging operation
Edition 26/08/2016
Malfunctions
In the event of malfunctions immediately deactivate the valve and secure it against inad-
vertent reactivation. Malfunctions may only be remedied by qualified staff, who must
observe the safety instructions.
Malfunction
Cause
Remedy
Valve does not work
Fault in the control system
Check the system configura-
tion
No compressed air or
compressed air too low
Check the compressed air
supply
Check air hoses for free
passage and air tightness
Fault in the electrical system
Check actuation / external
controller and routing of elec-
trical lines
Solenoid valve defective
Replace the solenoid valve
Valve works against a hydrauli-
cally closed pipe
Open the pipe
Double-disk oscillates during
lifting or does not open
Air pressure too low
Increase air pressure
Product pressure too high
Reduce product pressure
Valve does not close
Dirt/foreign material between
valve seat and valve disk
Clean valve housing and valve
seat
Valve closes too slowly
O-rings in actuator and control
module are dry (friction losses)
Grease O-rings
Leakage in the area of the
valve body
Housing O-rings defective
Disassemble the valve,
change the
housing O-rings
Leakage in the lantern
Sealing ring defective
Replace the sealing ring
Leakage in the leakage cavity
V-rings defective
Replace V-rings
