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13
TROUBLESHOOTING
For ease of service, the systems are equipped with diagnostic code
display LEDs on both the indoor and outdoor units. The outdoor
diagnostic display is an LED on the outdoor unit board and is
limited to very few errors. However, it is useful in identifying
special error codes like a failure of the outdoor coil sensor on heat
pumps. The indoor diagnostic display is a combination of flashing
LEDs on the display panel or the front of the unit. If possible,
always check the diagnostic codes displayed on the indoor unit
first.
The diagnostic codes for the indoor and outdoor units are listed in
the tables below.
INDOOR UNIT DIAGNOSTIC GUIDES
9K & 12K Units
Operation
Lamp
Timer
Lamp
Failure Mode
l X Indoor fan speed has been out of control for over 1 minute
l On Indoor room temp. or evaporator sensor is open circuit or short circuited
X l Compressor over---current protection has been activated four times
On l EEROM error
l l Indoor unit communication error (Illuminates simultaneously)
18K & 24K Units
Operation
Lamp
Timer
Lamp
Defrosting
Lamp
Auto
Lamp
Failure Mode
l l l l Over---current protection of the compressor occurs four times
X l X X Indoor room temp. sensor i s open circuit or short circuited
l X X X Temp. sensor on indoor evaporator is open circuit or short circuited
X X l X
Temp. sensor on outdoor condenser i s open circuit or short c ircuited (not cooling
only modes)
X X l l Outdoor unit protects (outdoor temp. sensor, phase o rder, etc.)
X l X l EEROM error
X X X l Indoor unit communication error
l =Flashing
X=Off
For additional diagnostic information, refer to the Service Manual.
A08486
A07544
A08483
HP Model size 009
HP Model size 01 2
HP Model size 018--024
TIMER
OPERATION
PRE-DEF
Infrared signal recepto
r
* PRE--DEF light will illuminate when the unit is running in FAN ONLY mode on Cooling Only units.
Note: Cooling only unitshave same LED lights butwithout PRE--DEF print.
Infrared signalreceptor
OPERATION
TIMER
PRE-DEF
AUTO
ECON
TIMER
PRE.-DEF*
AUTO
OPERATION
Fig. 21 --- LED Displa y Panel
OUTDOOR UNIT DIAGNOSTIC GUIDES
Flashing
Times after 2
Second Off
Failure Mode
Diagnostic
Chart
5 Communication failure 4or6
2 Condenser temperature sensor failure 2
1 Other indoor failure –
If the unit is operating normally, the LED light on the outdoor board is lit continuously. If there is a failure, the LED light will flash a specific
number of times. Refer to the Outdoor Unit Diagnostic table above to determine failure.
38/40MVC, MVQ