Carrier Central AC Error Codes &Troubleshooting (Detailed Steps)

Carrier air conditioner indoor unit
Figure 1: Carrier air conditioner.


The following gives a table of Carrier central air conditioner common error codes and troubleshooting methods for some of these codes.

1. Carrier Multi-Split Central Air Conditioning System P1 Error Code

Carrier 38VR multi-split common fault codes

Indoor unit

LED

Error code

Fault meaning

Running light flashes quickly

E2

Room temperature sensorfailure

Running light flashes quickly

E3

tube temperature sensor failure

Running light flashes quickly

E4

T2B tube temperature sensor failure

Running light flashes slowly

E7

EEPROM chip failure

Alarm light flashes quickly

EE

Water pumpfailure

Timer light flashes quickly

E1

Internal and external unit communication failure

Outdoor unit

E0

Communication failure

E1

Phase sequence fault

E5

Power supply voltage failure

H0

Communication failure between outdoor unit DSP and main control chip

H2/H3

The number of outdoor units decreases and faults increase

H7

Reduction in the number of indoor units

P1

High voltage protection

P2/H5

Low voltage protection

P4

System discharge temperature is too high

P3

Compressor current protection

P6

Frequency conversion module protection

P9

Fan modulefailure



Table 1: Carrier 38VR multi-split common fault codes explanation.


Fault code meaning: High voltage protection.

Causes and troubleshooting methods of Carrier multi-split central air conditioner P1 fault code:
1. Reset and restart the unit to confirm whether the fault persists. Directly press the reset button to try.
2. Too much refrigerant: Discharge the excess.
3. Air mixed in the refrigeration system: Re-evacuate the system and recharge it with refrigerant.
4. Dirty and blocked condenser coil: Please clean it.

5. Poor ventilation: It is recommended to check the ventilation of the air conditioner indoor and outdoor units. Poor heat dissipation of the condenser will also cause an alarm for excessive discharge pressure. Check and clean the dust on the condenser surface.

6. Blocked liquid pipeline: It is recommended to check whether the filter dryer and expansion valve are blocked.
7. Discharge pressure too high/low: It needs to find the cause and repair it in time.

8. Opening degree of the expansion valve too large: Appropriately reduce the opening degree.
9. High-voltage switch failure: If it is determined after inspection, just replace the switch directly.

10. Compressor failure: The compressor starts and stops frequently, which may be because the refrigeration oil level is too low, causing the alarm. Replenish the oil and check whether there is oil leakage from the compressor. If the compressor fails, repair or replace it with a new one in time.

11. Apply for repair: If the error repeats and cannot be cleared, it is recommended that you contact the after-sales service directly and professional maintenance personnel will come to your door for further inspection and troubleshooting.



Carrier wired controller for central air conditioning system
Figure 2: Carrier wired controller.

2. Carrier Multi-Split Central Air conditioning System System E1 Error Code

Fault code meaning: Phase-sequence failure.

Causes and troubleshooting methods of Carrier multi-split central air conditioner E1 fault code:
1. Reset and restart the unit to see if the error code is cleared.
2. The input terminal of the power line on the I/O board is loose. Solution: Tighten the wiring screws appropriately.
3. Some components of the power line input side on the I/O board are aging or burned out. Solution: Replace damaged components.

4. Apply for repair: If the error repeats and cannot be cleared, it is recommended that you contact the after-sales service directly and professional maintenance personnel will come to your door for further inspection and troubleshooting.

3. Carrier Multi-Split Central Air conditioning System E0 Error Code

Fault code meaning: Communication failure.
When the Carrier central air conditioning displays E0 error code, check the status of all communication lines and main electronic control components of the system. Abnormal communication failures in the air conditioning system are mostly caused by abnormal damage to the main electronic control components of the air conditioner, partial looseness of the communication lines, abnormal dust accumulation in the connection parts, moisture, etc.



Carrier air conditioning control panel
Figure 3: Carrier air conditioning control panel.


Causes and troubleshooting methods of E0 fault code of Carrier multi-split central air conditioner
1. Reset and restart the unit to confirm whether the fault persists. Directly press the reset button to try.

2. Voltage problem: If the voltage is abnormal or the outdoor unit is very hot, it means that the frequency conversion module needs to be replaced with a new one.

3. Problems with the outdoor unit: If the outdoor fan rotates slowly or occasionally does not rotate, it means there is something wrong with the fan. Replace it and try again.
If the outdoor fan does not work, the compressor starts and then stops, and the error code is displayed, it indicates that the main control circuit board of the outdoor unit does not supply power to the outdoor fan. Check the relay, thyristor or replace the main board of the outdoor unit.

4. Communication system problem: Replace the internal and external unit signal connection cables. If the fault still exists, measure the power supply voltage of the signal port of the external unit control board. If there is a voltage of 3-5V, it means there is no problem with the communication system, and the problem comes from the frequency conversion motherboard or module.

5. Main unit circuit problem: There should be a wiring diagram on the power cover of the outdoor unit and check whether the wiring is wrong according to it.

6. Apply for repair: If the error repeats and cannot be cleared, it is recommended that you contact the after-sales service directly and professional maintenance personnel will come to your door for further inspection and troubleshooting.



a fan for an air conditioner outdoor unit
Figure 4: Outdoor fan.

4. Carrier Multi-Split Central Air Conditioning System E5 Error Code

Fault code meaning: Power supply voltage failure. It could be caused by low voltage, power outage, blown fuse or incorrect wiring.

Causes and troubleshooting methods of Carrier multi-split central air conditioner E5 fault code:
1. Reset and restart the unit to confirm whether the fault persists. Directly press the reset button to try.
2. Power outage or blown fuse: Check whether the circuit is open or replace the blown fuse.
3. Wiring error: Check and correct the wiring according to the circuit diagram.

4. Wrong voltage phase sequence: Exchange the phase sequence.
5. Low power supply voltage: After inspection, restore the normal voltage value.
6. Last fault not reset: Press the fault reset button.

7. Apply for repair: If the error repeats and cannot be cleared, it is recommended that you contact the after-sales service directly and professional maintenance personnel will come to your door for further inspection and troubleshooting.

5. Carrier Central Air Conditioning System Maintenance

5.1 Carrier Central Air Conditioning System Routine Inspection

Carrier XCT8 series multi-split air conditioner
Figure 5: Carrier air conditioner.


1. Check the temperature and pressure of the cooling water at the inlet and outlet;
2. Check the temperature and pressure of the chilled water at the inlet and outlet;
3. Check for noises, vibrations, and abnormal pressure;
4. Check whether the power supply and main line wiring are damaged, broken, loose, or rubbed;
5. Check the refrigeration oil level and whether the refrigerant is sufficient.
6. Check whether there are air bubbles in the system, causing abnormal pressure. If bubbles are found, evacuate the system in time.

5.2 Carrier Central Air Conditioning Electronic Control System Maintenance

1. Use a blower to blow off dust, floating objects, debris, etc. inside and outside the electrical box to keep it clean.
2. Check the terminals, screws, screw heads, etc. between the wire connectors of each circuit. If any are found loose, tighten them with a screwdriver in time to prevent other failures caused by poor contact.
3. Check and tighten the electrical screws related to relays, intermediate relays, intermediate contactors, circuit breakers, leakage protections, phase sequences, etc.
4. Check whether the mainboard of the microcontroller and the output and input signal lines are normal, and whether the wiring is firm and reliable.
5. If there is a problem with the PC processor or printed circuit motherboard, please promptly report it to the manufacturer.

a man is cleaning the air conditioner indoor unit
Figure 6: Air conditioner cleaning.

5.3 Carrier Compressor Maintenance and Inspection

1. Check whether the insulation resistance and ground resistance of the compressor motor are normal, the value of which normally is above 0.5 ohms;
2. Check whether the three phases of the compressor are balanced and whether the operating current is within the rated value range. If not, check the detailed situation and the fluctuation is allowed to be 5%-10%.
3. Check whether the oil pressure difference of the compressor is normal, and it should be about 15KG or up or down.
4. Check whether the suction and discharge pressure is normal. The suction pressure is about 5KG and the discharge pressure is about 13KG. The fluctuation is allowed to be 5-10%, depending on the situation.
5. Check whether there is any peculiar smell in the compressor, and judge whether there is a fault based on the above parameters and experience. If you are uncertain, please contact professional persons for help.

Submitted Successfully
Submission Failed