English (GB)
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6.10 Possible faults
7. Maintenance
Rates for cleaning and maintenance
• at least every 12 months
• in case of malfunction
7.1 Maintaining the servomotor
8. Disposal
This product or parts of it must be disposed of in an
environmentally sound way:
1. Use the public or private waste collection service.
2. If this is not possible, contact the nearest Grundfos company
or service workshop.
Subject to alterations.
Fault
Cause
Correction
Despite constant operating
conditions the vacuum varies
Spring in differential pressure regulator is soiled
Call the service
Spring in differential pressure regulator is
damaged
Call the service
Despite constant operating
conditions the dosing flow varies
Diaphragm in differential pressure regulator is
soiled
Call the service
Diaphragm in differential pressure regulator is
damaged
Call the service
Leakage at the rate valve
Bar gasket in the rate valve damaged
Call the service
Floater of the measuring tube is
not caught
Measuring tube is soiled
Clean the measuring tube
Desired dosing flow is not
reached
Insufficient injector vacuum
Check injector, observe the manual of the
injector
Servomotor (option) does not reach the 100 %-
position
Call the service
Leakage in vacuum line between differential
pressure regulator and injector
Eliminate leakage (see "checking the tightness")
Vacuum line between differential pressure
regulator and injector too long
Observe table "Recommended diameter" in
chapter
Vacuum line between vacuum regulator and gas
dosing system too long
Admission pressure at the vacuum regulator too
low
If necessary, open gas supply or clean filter
(observe manual of the vacuum regulator)
Regulating channel of the adjusting plunger soiled Call the service
Despite correctly displayed gas
flow the desired gas solution
concentration cannot be reached
Leakage in vacuum line between vacuum
regulator and gas dosing system
Eliminate leakage (see "checking the tightness")
Servomotor does not run
Servomotor is switched to manual operation
Switch servomotor to automatic operation
Servomotor does not reach the
whole range desired
Servomotor resp. electronics adjusted wrongly
Call the service
Servomotor runs in wrong
direction
Servomotor resp. electronics adjusted wrongly
Call the service
The adjusting spindle falls from
the "automatic" position into the
"manual" position unintentionally
The spring-loaded thrust pad has been displaced
and therefore cannot deliver enough preload to
the holding groove of the adjusting spindle.
Adjust the thrust pad.
The spring-loaded thrust pad is damaged.
Exchange the spring-loaded thrust pad
(96690346 or 50.1340); gently press on the ball.
The adjusting spindle must be able to move up
and down.
Warning
Do not open the components of the device!
Cleaning, maintenance and repair only by authorized
personnel!
Warning
Switch off the whole plant before doing cleaning and
maintenance work!
Danger of gas break-out!
Warning
Check the tightness before restarting!
Danger of gas break-out!
Note
The servomotor features permanent lubrication and
is maintenance-free.
Warning
The entire installation should be switched off before
any repair work is carried out.
Disconnect the mains voltage before opening the
housing!
