Lauda UB 20 - Page 79

Notes for trouble-shooting for
LAUDA Thermostats with P - electronics
G/Therm/Service/Fehler/Fehlpe1.doc
- 04.12.98 page 3 of 4
Malfunction Fault Reason Remedy
Display:
“Internal Pt 100
defective”
Double Pt 100 for bath
temperature or safety
temperature
Interruption, short circuit or
temperature deviation of bath
temperature probes too
important
Replace double Pt 100 for bath
temperature
For USH 400(/6) please check
both single Pt 100
Display:
“Ext. Pt 100 not
connected”
Tried to switch over to external
control without connecting an
external Pt 100
Continue to work with internal
control or connect external Pt 100
for T1 or T2; look at display for
control variables I, 1 or 2; check
display for T1 or T2
Tried to calibrate Pt 100 being
not connected
Display:
“Correcting value too
high”
Important deviation of Pt
100 from standard values
Value input differing from the
basic value that is indicated by
more than 5 K
Check temperature reference
thermometer, check Pt 100;
replace PCB ”CPU”
Scale of analogue
outputs shows
discrepancies
Outputs not correctly calibrated Calibrate the analogue output
channels
(see operating instructions)
Unit does not heat
though heating is
indicated
Triac Replace triac
Heater Defective Replace heater
Interruption Eliminate
Electronics Replace PCB ”MP Mains”
Controller output limitation at
PAR level too small
Enter higher values at PAR level
( e.g. 100 % )
Pump does not run Temperature safety cut-out
in pump has actuated
Pump stops
Motor blocked Turn propeller of motor; if
necessary replace it; clean pump
Viscosity of bath liquid too high Use other bath liquid; wait until
motor has cooled down
Bath temperature rises
clearly above adjusted
setpoint ( Ts )
Heating indication ON
Controller Replace PCB ”MP Mains” or PCB ”
CPU ”
Heating indication OFF Triac Replace triac
Temperature rises slowly
above adjusted setpoint
Heating indication OFF
Cooling not sufficient Heat emission of pump Connect cooling water supply or
other kind of cooling
Display shows wrong
temperature ( Ti, T1, T2 )
Temperature probe Replace double Pt 100 or external
Pt 100 T1, T2
Display is dark Temperature cut-out in
transformer has actuated
Overload caused by short –
circuit
Replace PCBs or control unit