-6-
C. Fault finding
Symptoms
Possible cause
Action
Valve does not open
One-way flow restrictor blocked Replace or unscrew the set
screw several times until the
valve functions properly
One-way flow restrictor closed
too far
Screw the set screw in and out
until the valve functions properly
Solenoid valve does not work
Check the function (electrical
work may only be carried out by
specialist personnel)
Valve does not close
One-way flow restrictor blocked Replace, or screw the set screw
fully in and out several times
and then re-set
Filter in the control line blocked
Clean the filter
Air in the control line / upper
valve chamber
Vent
Foreign matter in the main valve Carry out service and remove
any foreign matter
Diaphragm defective
Carry out a service.
Replace the diaphragm
Valve spindle jammed by
encrustation
Carry out service and remove
any encrustation
Solenoid valve does not work
Check the function (electrical
work may only be carried out by
specialist personnel)
Loud noise
Unfavourable operating
conditions
Slightly open or close the one-
way flow restrictor; Inform Field
Service
Wrong valve size
Have the correct valve size
calculated (contact Hawle)
Erratic operation
One-way flow restrictor
incorrectly set
Re-set as described in the
Setting the Reaction Speed
chapter
EWS coating damaged
Transportation damage,
installation damage
Repair with Hawle two-
component repair set for
coatings
