8 - DIAGNOSTICS
50
8.6 - Alarm codes
Alarm No.
ALARMRST
Code
Description of the alarm text
Reset type
Probable cause
Action taken by the
control
Sensor Failures
1
Th-204
Indoor air Thermistor #1
Automatic if the
temperature
measured by the sensor
returns
to normal
Defective thermistor
Unit is shut down
2
Th-205
Indoor air Thermistor #2
As above
As above
As above
3
Th-202
Supply air Thermistor
As above
As above
As above
4
Th-206
Space Temperature Offset
As above
As above
Space temperature
offset
function is ignored
5
Th-203
Return Air Thermistor
As above
As above
Unit is shut down
6
Th-02
Water exchanger Leaving Fluid
Thermistor
As above
As above
Hot-water coil disabled
7
Th-03
Circuit A Defrost Thermistor
As above
As above
Unit is shut down if
heating mode
8
Th-04
Circuit B Defrost Thermistor
As above
As above
As above
9
Th-10
OAT Thermistor
As above
As above
Unit is shut down
10
Th-12
Circuit A EXV Suction Thermistor
As above
As above
As above
11
Th-13
Circuit B EXV Suction Thermistor
As above
As above
As above
12
Th-14
Circuit THR EXV Suction Thermistor
As above
As above
As above
13
Th-11
Mixed Air Thermistor
As above
As above
unit is shut down
14
Pr-01
Circuit A Discharge Transducer
Automatic when the
voltage transmitted
by the sensor
returns to normal
Defective transducer
or installation fault
Circuit is shut down
15
Pr-02
Circuit B Discharge Transducer
As above
As above
As above
16
Pr-03
Circuit THR Discharge Transducer
As above
As above
As above
17
Pr-04
Circuit A Suction Transducer
As above
As above
As above
18
Pr-05
Circuit B Suction Transducer
As above
As above
As above
19
Pr-06
Circuit THR Suction Transducer
As above
As above
As above
20
Se-201
Indoor Air Quality sensor
As above
defective sensor
Indoor air quality
function is
disabled
21
Se-203
Relative Humidity sensor
As above
As above
Humidity control function
is disabled
Communication
Failures
22
Co-S1
Loss of communication with
SIOB Board Number 1
Automatic if
communication is
re-established
Installation bus fault
or defective
board
Circuit A is disabled
23
Co-S2
Loss of communication with
SIOB Board Number 2
As above
As above
Circuit B is disabled
24
Co-S3
Loss of communication with
SIOB Board Number 3
As above
As above
Circuit C is disabled
25
Co-A1
Loss of communication with AUX1
Board Number 1
As above
As above
Compressor VSPD is
disabled
Process
Failures and
Others
26
P-01
Water Exchanger Freeze
Protection
Manual
Heat exchanger water
below
2.5 °C
Indoor fan is off, 3 way
valve bypass line is
closed to enable hot
water pass inside the
coil
(
hot-water system
feed).
27
P-05
Circuit A Low Suction
Temperature
Automatic when the
temperature
returns to normal,
and if this
alarmhas not
appeared during
Pressure sensor
defective, EXV
blocked or low
refrigerant charge
Circuit is shut down
