898150-UIM-B-0113
Johnson Controls Unitary Products
25
INDOOR UNIT ERROR CODES
TABLE 12:
Error Codes
Indoor Character
Display
System Status
Troubleshooting for
Possible Causes
b5
RT1 room temperature sensor
malfunction
Cooling and dehumidification modes will
continue to operate as well as indoor fan.
Unit will not operate in heating mode.
• Check sensor to ensure that it is in
acceptable range.
• Check sensor for proper resistance.
• Replace sensor if shorted, open or out-
of-calibration.
b7
RT2 coil temperature sensor
malfunction
C5
Indoor control jumper is
missing (labeled JUMP)
All system functions are terminated.
Check indoor control jumper connections
and replace jumper, if missing.
dd Pre-operation
function
When unit is set to cooling mode and set
point is 86ºF (30ºC), press the remote -
and + button in the following sequence ( -
+ - + - +) for three seconds to place the
unit in pre-operation mode. This cooling
operation with the indoor fan off and dd is
displayed on indoor unit.
Normal system operation
dn Pre-operation
function
error
If during pre-operation mode, if it is deter-
mine that the unit is wired incorrectly or the
expansion valve has malfunction this code
will display.
• Check expansion valve • Check wiring.
EE
Intelligent Power Module
protection limit
System will continue to run; however at
reduced compressor speed until issue is
corrected.
Replace outdoor control.
EU
Intelligent Power
Module protection limit
All system functions are terminated.
Intelligent Power Module protection limit
error can result from any of the following:
• Loss of cooling to the heat sink
• Low voltage
• High ambient temperature
• Loose screws fastening the outdoor con-
trol to the heat sink
Check all and correct, if necessary, refer to
the ProficienTECH Ductless Splits Techni-
cal Training Manual.
E1 System
high
pressure
All system functions are terminated except
indoor fan.
• Outdoor unit high pressure switch is
disconnected or has malfunctioned.
• Verify connection to outdoor control. If
connection is verified and system is still
displaying E1, re-place high pressure
sensor.
E2
Indoor coil freeze protection
All system functions are terminated except
indoor fan. The indoor coil sensor (RT2)
monitors the coil temperature continu-
ously. If coil temperature drops below
30.2ºF (-1ºC), the compressor and the out-
door fan (30 seconds later) are switched
off. Condition is cleared when indoor coil
temperature rises above 42.8ºF (6ºC) and
the compressor has been off for a mini-
mum of three minutes.
• Check for restricted indoor airflow and
change filter, if necessary.
• Check for restricted refrigerant flow.
• Check for low outdoor ambient tempera-
ture or low indoor system load.
E3
Low pressure protection
All system functions are terminated except
indoor fan.
• Check for proper clearances around
outdoor unit.
• Check outdoor coil for and clean, if
necessary.
