22
Controller Troubleshooting.
The following table shows a number of anomalous situations that may occur on the various
models.
The most frequent causes and corresponding checks are described:
Problem
Cause
Checks
the compressor does not start (signalled by the
compressor LED flashing)
• compressor delay set
• defrost post dripping in progress
parameters c0, c1 and c2 and dd
the temperature is over the set limits but there is
no alarm message and the buzzer, if fitted, does
not sound
alarm delay set
parameters Ad, c6, d8
alarm IA is signalled (multifunction input) without
actually being active
the multifunction input generates an alarm when
the contact opens
connection of the input and whether this is closed
in normal operation
the alarm connected to the multifunction input is
not detected
alarm delay set or parameter programming error
1. if A4=1
2. the status of digital input A7
the defrost is not activated
• defrost duration too short (dP)
• interval between defrosts dI=0: in this case the
defrost is not activated
parameters dP and dI
the end defrost temperature is too low or the
evaporator temperature is too high
parameters dt and d/ (defrost probe)
the manual defrost is not activated and the defrost
LED flashes
compressor protection times set
parameter d9 (select d9=1)
the high temperature alarm is shown after a
defrost
the alarm delay after defrost is too short or the
alarm threshold is too low
parameters d8 and AH
the display remains frozen even after the defrost
the ambient temperature has not yet reached the
set point or alternatively the time d8 has not
elapsed
wait or reduce d8
after modifying a parameter the controller
continues working with the old values
the instrument has not updated the old value or
alternatively the parameter setting procedure has
not been ended correctly by pressing the SET
button for 3 s
turn the instrument off and on again or
alternatively reprogram the parameters correctly
the evaporator fan does not start
1. a compressor and fan start delay has been set
2. if F0=1 (fan managed by fan controller)
• the evaporator is “hot”: the evaporator
temperature can be read by selecting
parameter /d;
• dripping in progress;
• F1 (evaporator fan control set point) too low.
• post-dripping delay set
3. if F0=0
• F2=1 and the compressor is off
• dripping in progress
• post-dripping in progress
1. parameter c0
2. parameters F0, F1, Fd, dd and d/
3. parameters F0, F2, dd and Fd
Summary of Contents for SMART 7 STI022LR404A2
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