12-2
TROUBLESHOOTING
SM DUO38I 1-A.2 GB
1.2 Checking the refrigeration system
Checking system pressures and other thermodynamic measures should be done when system is in
Test Mode (in Test mode, system operates in fixed settings). The performance curves given in this
manual are given for unit performance in test mode when high indoor fan speed is selected.
Entering test mode:
Set the two indoor units to Cool/16 degrees/High indoor fan speed, or Heat/30 degrees/High indoor
fan speed, and enter diagnostics. Note: the two indoor units should be set to the same mode and fan
speed.
1.3 Judgment by MSMP Diagnostics
The MSMP controller has 11 LED’s (1 STBY LED, 5 Unit LEDs and 5 Status/Fault LEDs).
STBY LED is ON when power is ON.
5 Unit LEDs refer to four Indoor units and one Outdoor unit. They will turn on one at a time and the
corresponding Indoor/Outdoor unit status/fault code will be displayed on the Status/Fault LEDs. If
the unit is normal (no fault), the unit LED and the corresponding status will be displayed for 5
seconds and move to the next unit LED. On the other hand, if the unit is in fault, the unit LED and
the corresponding fault will be displayed for 10 seconds, and hence more time to read the fault code.
1.3.1 MSMP Fault Code for Outdoor unit:
No
Problem
5
4
3
2
1
1
OCT is disconnected
0 0 0 0 1
2
OCT is shorted
0 0 0 1 0
3
CTT is disconnected
0 0 0 1 1
4
CTT is shorted
0 0 1 0 0
5
HST is disconnected (when enabled)
0 0 1 0 1
6
HST is shorted (when enabled)
0 0 1 1 0
7
OAT is disconnected (when enabled)
0 0 1 1 1
8
OAT is shorted (when enabled)
0 1 0 0 0
9
TSUC is disconnected (when enabled)
0 1 0 0 1
10
TSUC is shorted (when enabled)
0 1 0 1 0
11 IPM
0 1 0 1 1
12
Bad Outdoor unit EEPROM
0 1 1 0 0
13
DC under voltage
0 1 1 0 1
14
DC over voltage
0 1 1 1 0
15
AC under voltage
0 1 1 1 1
16
Indoor / Outdoor unit Communication mismatch
1 0 0 0 0
17 No
Communication
1 0 0 0 1
18
Illegal Outdoor unit Model
1 0 0 1 0
19
Bad MSMP EEPROM
1 0 0 1 1
20
Heat sink Over Heating
1 0 1 0 0
21 Deicing
1 0 1 0 1
22
Compressor Over Heating
1 0 1 1 0
23
Compressor Over Current
1 0 1 1 1
…. Reserved
27 Bad
Communication
1 1 0 1 1
… Reserved
29
No Fault (Heat Mode)
1 1 1 0 1
30
No Fault (Cool, Dry, Fan Mode)
1 1 1 1 0
31
No Fault (Stand By)
1 1 1 1 1
