
We reserve the right to make changes without prior notice
96
CODE
DESCRIPTION
MAIN CAUSE POTENTIAL
RESOLUTION OF THE PROBLEM
RESET
UNIT
OFF
DEVICES
SWITCHED
OFF
AL17 Not
used
AL18
Flow switch alarm
The air flow switch has tripped: it
indicates a lower air differential
pressure than the calibration setpoint, in
other words an air flow rate failure.
Check the operating conditions (air flow
rate and discharge head).
Check the air delivery fans for correct
operation.
Check the air distribution system.
Check the air flow switch for correct
calibration and operation.
M Yes
All
AL19
Clock board
malfunctioning or
missing
The controller cloak board is
malfunctioning.
Power the unit controller down and up
again; if the alarm persists, replace the
controller board.
M No
None, but time
slot
management
does not work.
AL20
Summer setpoint <
winter setpoint
The summer setpoint of the ambient
temperature is inferior to the winter
setpoint. Alternatively, the winter
setpoint is higher than the summer
setpoint, and the summer/winter mode
shift is enabled to “automatic”.
Set the summer and winter temperature
setpoints correctly.
A Yes
All
AL21
Probe U1
malfunctioning or
disconnected
The value measured by probe U1
(differential air pressure of fans in
delivery line) 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
AL22
Probe U2
malfunctioning or
disconnected
The value measured by U2 (differential
air pressure of fans in return line) 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
AL23
Probe U6
malfunctioning or
disconnected
The value measured by probe U6
(differential air pressure of fans in circuit
2) 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
AL24
Probe U7
malfunctioning or
disconnected
The value measured by probe U7 (air
humidity in return line) 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
AL25
Probe U4
malfunctioning or
disconnected
The value measured by probe U4 (air
temperature in return line) 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
AL26
Probe U3
malfunctioning or
disconnected
The value measured by probe U3
(condensing pressure in circuit 1) 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