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16. TIPS FOR TECHNICIANS
The following trouble shooting guide is intended solely for technical staff. Repairs
may only be carried out by technicians.
Possible Cause
• Absence of mains power.
• Pressure switch not
switched on.
• Under voltage/Over voltage.
• Motor protection switch set
too low.
• Motor protection switch
defective.
• Air-relief valve defective,
compressor set starting up
against pressure (only
compressors without
dry-air system).
• Set reveals mechanical
sluggishness, piston stuck
(motor protection switch
trips)
Fault
1. Compressor fails
to start up.
Removal of Fault
• Check mains fuse, switch unit
back on again if necessary (if fuse
is defective, replace). Check mains
voltage.
• Switch on pressure switch.
If the pressure switch remains
switched on for a brief duration
and does not switch the motor off
until afterwards, the current
consumption on the 3-phase
current needs to be checked in all
three phases or in one phase on
AC current.
• Measure voltage, notifying the
electrician if necessary.
For a detailed description
refer to Section 8.5 "Setting
the Motor Protection Switch".
• Measure current. Set motor
protection switch accordingly (refer
to Chapter 4. "Technical Data").
• Check motor protection switch,
replacing if necessary.
• Check to see whether the air-relief
valve produces blowoff after the
set is switched off. Render
operable or replace.
• Disconnect mains plug, remove
crankcase cover on compressor
that has heated and turn fan
wheel; if this is not possible,
replace piston and cylinder or
complete set.
Users of model Duo-,
Quattro Tandem may
temporarily utilize only one
aggregate.
