JULABO LH 85 High Dynamic Temperature System - Manual (Page 61)

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9.1. Additional warnings and alarm messages LH85
In order to guard against a destruction of particular components of the
refrigerant cycles, different control sensors were installed. The following
messages explain the particular incidences and give indication for further
action.
WARNING
CODE 27
The compressors of both stages were switched off.
The high pressure controller in 1
st stage measures a too high pressure. As
soon as the pressure in stage 2 reaches the lower switching point, the
compressors are switched on again delayed.
WARNING
CODE 28
The compressor of both stages were switched off.
The exit temperature of stage 1 is too high. As soon as the temperature
reaches the lower switching point, and – as second condition – the pressure
proportions allow it, the compressors are switched on again delayed.
ALARM
CODE 29
The exit temperature of stage 1 is too high. For this reason the compressors
of both stages have already been switched off 4 times.
(see warning CODE 28).
After a cool-down phase the alarm status can be cancelled by switching off
and on again at the mains switch, and the unit is ready to operate again.
In order to avoid the destruction of the compressor, the refrigerant cycle of
1
st stage should be checked by a specialist first.
ALARM
CODE 30 The temperature sensor for the exit temperature of stage 1 is bypassed, or
there is a line interruption.
Have the repair done by a specialist. .
WARNING
CODE 42 Already for a period of 5 minutes the pressure in stage 2 (high pressure
side) is too high. The cooling system works at its limit. If the pressure falls
below a factory-made value for at least 100 seconds, the warning expires
again.
WARNING
CODE 43 The compressor of stage 2 was switched off.
The high pressure controller in stage 2 (high pressure side at approx. 24
bar) measures a too high pressure. As soon as the pressure reaches the
switching point again, the compressor is switched on and the warning
expires again.
WARNING
CODE 44
The compressor of stage 2 was switched off.
The high pressure controller T0 in stage 2 (low pressure side at approx. 7
bar up to 9,5 bar) measures a too high pressure. As soon as the pressure
reaches the lower switching point again, the compressor is switched on,
and the warning expires again.