Grant Instruments LTC4 - Manual (Page 36)

31115 V1 LTC4
Page 35 Operating Manual
www.grantinstruments.com
11.0 Troubleshooting
Symptom Possible cause Action required
Unit fails to cool Compressor
overheated causing
internal over-
temperature
thermostat to operate
Wait for compressor to cool, when thermostat
will reset and compressor will switch on again.
Unit failing to
cool below 5°C Freezing protection
switch is on and is
preventing further
cooling
Switch off freezing protection (see section
5.2.7).
Unit not cooling
at higher
temperatures Over temperature
protection switch has
tripped Refrigeration unit may have temperatures in
excess of 100°C. Leave the unit to cool and
reset (see section 5.2.7)
Cooling
performance
reduced Condenser fins
clogged Carry out routine cleaning (see section 9.2)
Temp continues
to rise when not
expected Set temp is higher
than liquid temp
Check that the bath set temperature is correct
(see section 5.2.10).
Set temperature
too restricted Liquid type set does
not allow required set
point Change to different liquid type (see section
5.3.2).
Temperature
does not rise
when expected Set temp is lower
than liquid temp
Check that the bath set temperature is correct
(see section 5.2.10).
Display shows
“High
Temperature
Alarm” High temperature
warning alarm has
tripped Check that the bath set temperature is correct
(see section 5.2.10).
Check that high temperature alarm is correct
(section 5.3.4).
Check that the liquid level in the bath is
adequate (see section 5.1.1 for minimum fill
levels).