
We reserve the right to make changes without prior notice
99
CODE
DESCRIPTION
MAIN CAUSE POTENTIAL
RESOLUTION OF THE PROBLEM
RESET
UNIT
OFF
DEVICES
SWITCHED
OFF
AL77
Circuit 2
Low pressure from
heating transd.
Tent.: x/y
A high pressure alarm has triggered in
refrigerant circuit 2 - heat pump mode -
generated by the pressure transducer.
The display shows trip “x” out of the
max. number “y” of trips, after achieving
which the alarm must be reset
manually.
Check the operating conditions.
Check the condensing pressure.
Check the refrigerant level.
Check the condensation fans.
Manually reset the high pressure switch
before resetting the alarm on the display.
Check for correct operation of the high
pressure switch.
AC No
All
compressors in
circuit 2
AL78
WARNING
Circuit 1 in Prevent
low pressure
The evaporation pressure in circuit 1 -
winter mode - is lower than the Prevent
value.
Check the operating conditions.
Check the refrigerant level.
A (3)
No
One
compressor in
circuit 1
AL79
WARNING
Circuit 2 in Prevent
low pressure
The evaporation pressure in circuit 2 -
winter mode - is lower than the Prevent
value.
Check the operating conditions.
Check the refrigerant level.
A (3)
No
One
compressor in
circuit 2
(1) maintenance alarms must be reset in screens Ac-Ad-Ae of the Maintenance menu: they are not reset
by clicking the Alarm button.
(2) Alarms relating to the EVD drivers in circuits 1 and 2 must be reset in screens Au and Av of the
Maintenance menu respectively: they are not reset by clicking the Alarm button.
(3) The alarm is reset automatically: it is deleted from the list of the active alarms by pressing the Alarm
button for at least 2 seconds.