Troubleshooting - Carrier 40MVC Installation Instructions Manual

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 Timer
Lamp Lamp Failure Mode
€_ X Indoor fan speed has been out of control for over 1 minute
€_ On Indoor room temp. or evaporator sensor is open circuit or short circuited
X €_ Compressor over-current protection has been activated four times
On €_ EEROM error
€_ €_ Indoor unit communication error (Illuminates simultaneously)
18K & 24K Units
Operation Timer Defrosting Auto
Lamp Lamp Lamp Lamp Failure Mode
€_ €_ €_ €_ Over-current protection of the compressor occurs four times
X €_ X X Indoor room temp. sensor is open circuit or short circuited
€_ X X X Temp. sensor on indoor evaporator is open circuit or short circuited
X X €_ X Temp. sensor on outdoor condenser is open circuit or short circuited (not cooling
only modes)
X X €_ €_ Outdoor unit protects (outdoor temp. sensor, phase order, etc.)
X €_ X €_ EEROM error
X X X €_ Indoor unit communication error
€_ = Flashing
X = Off
For additional diagnostic information, refer to the Service Manual.
Infrared signal receptor
/
OPERATION AUTO TIMER
0 0 0
ECON PRE-DEF
o o o
HP Model size 009
Infrared signal receptor
/
A07544
HP Model size 012
* PRE-DEF light will illuminate when the unit is running in FAN ONLY mode on Cooling Only units.
Note: Cooling only units have same LED lights but without PRE-DEF print.
Fig. 21 - LED Display Panel
AUTO TIMER PRE.-DEF* OPERATION
A08483
HP Model size 018-024
OUTDOOR UNIT DIAGNOSTIC GUIDES
Flashing Diagnostic
Times after 2 Failure Mode
Second Off Chart
5 Communication failure 4 or 6
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.
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