
Notes for trouble-shooting for
LAUDA Thermostats with P - electronics
G/Therm/Service/Fehler/Fehlpe1.doc
- 04.12.98
page 4 of 4
Malfunction
Fault
Reason
Remedy
Unit does not work at
adjusted setpoint
Wrong control parameters
adjusted
Enter new values or start
autoadaption
Temperature control by
means of external
controller not stable
Thermal contact of bath liquid
and external measuring point
not sufficient
Improve circulation through
external consuming device or
thermal contact to ext. Pt 100
Unit does not cool down
Controller output limitation at
PAR level too small
Adjust higher value at PAR level
( e.g. -100 % )
Compressor defective
Replace refrigeration unit – by
refrigeration engineer !!
Leakage in refrigeration
system
Clear leakage, fill in refrigerant –
by refrigeration engineer !!
Compressor does not run
Compressor without tension
Eliminate line interruption
Triggering defective
Replace PCB ”MP Mains ”
Unit does not cool down
Compressor does not run
Pressure switch has actuated
Unscrew grid, clean condenser,
blow through compressed air,
improve ventilation
Solenoid valves do not
work correctly
Triggering defective
Replace PCB ” MP Mains ”
Compressor switches ON
and OFF in regular
periods; temperature
constancy very bad
Condensation pressure too
high
Fan defective
Replace fan motor
Fan speed ( only RK )
Check speed or speed controller
Condenser dirty
Dust
Unscrew grid, from the back side
blow compressed air or nitrogen
through condenser
Ventilation disturbed
Enlarge distance to nearby units or
walls
Ambient temperature too high
Air the room
Insufficient cooling in the
lower temperature range
Bath liquid contaminated by
condensate
Replace bath liquid to suit bath
temperature
Cools down to approx. 0°C
only
Bath liquid not suitable ( water )
Use water/ glycol mixture