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98
CODE
DESCRIPTION
MAIN CAUSE POTENTIAL
RESOLUTION OF THE PROBLEM
RESET
UNIT
OFF
DEVICES
SWITCHED
OFF
AL69
Differential probe in
return line
The differential air pressure probe in the
return line has detected a value outside
the min. and max. setpoints stored in
controller screen Y6.
Check the air flow rate in the return line.
Check the air distribution system.
Check for correct operation of the
differential air pressure probe and correct
positioning of the pipes for pressure
measurement.
A (3)
No None
AL70
Probe U9
malfunctioning or
disconnected
The value measured by probe U9 (CO
2
probe) is outside the operating range.
Check the operating conditions.
Check the probe setpoint range stored in
the controller.
Test the probe: if it does not work
correctly, replace it.
Check the electrical connection of the
probe.
Check the input of the controller board.
M No
All devices and
functions
whose setting
is connected to
the probe
AL71
Probe U10
malfunctioning or
disconnected
The value measured by probe U10
(external air relative humidity) is outside
the operating range.
Check the operating conditions.
Check the probe setpoint range stored in
the controller.
Test the probe: if it does not work
correctly, replace it.
Check the electrical connection of the
probe.
Check the input of the controller board.
M No
All devices and
functions
whose setting
is connected to
the probe
AL72
Board 2
LAN disconnected
Communication has been disrupted with
the controller expansion board.
Check that the expansion board is
powered correctly.
Check the connection between the
expansion board and the controller board.
Check the communication parameters.
M No
All devices and
functions
whose setting
is connected to
the probes
plugged into
the expansion
board
AL73
B1 in board 2
malfunctioning or
disconnected
The value measured by probe B1 in the
expansion board is outside the
operating range.
Check the operating conditions.
Check the probe setpoint range stored in
the controller.
Test the probe: if it does not work
correctly, replace it.
Check the electrical connection of the
probe.
Check the input of the controller board.
M No
All devices and
functions
whose setting
is connected to
the probe
AL74
Circuit 1
High pressure from
cooling transd.
Tent.: x/y
A high pressure alarm has triggered in
refrigerant circuit 1 - cooling 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 1
AL75
Circuit 2
High pressure from
cooling transd.
Tent.: x/y
A high pressure alarm has triggered in
refrigerant circuit 2 - cooling 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
AL76
Circuit 1
Low pressure from
heating transd.
Tent.: x/y
A low pressure alarm has triggered in
refrigerant circuit 1 - 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 1