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2-WAY MULTISET VRF SYSTEM
Trouble Diagnosis
7
1.
2WAY VRF DCI
Alarm Codes
CT circuit failure
H13, H23 Alarm
Alarm code
H13, H23
Alarm meaning
Compressor 2 CT sensor (CT2) disconnected or short-circuit; Compressor 3 CT sensor (CT3)
disconnected or short-circuit.
Alarm conditions
The current is still 1.5 A or less when 2 seconds or longer has elapsed after output from that
compressor started.
* No current is detected even though the compressor is operating.
Probable cause
(1) CT circuit failure (including cut wiring, etc.)
(2) Disconnected CT circuit connector
(3) Missing phase where CT circuit is connected
(4) This CT circuit is connected to the connector of other CT circuit.
(5) PCB failure
Check
(1) CT circuit failure, PCB failure
Trouble: • Current value during compressor operation is below the threshold value.
Check:
• Check that the connector is not disconnected.
• Check the continuity of the CT circuit.
• Install a normal CT in place of this CT and check. If current is detected, then the
PCB can be judged OK.
• Check that current is flowing in the phase where the CT circuit is connected.
→
Check voltage and current.
(2) Crossed wiring or installation error
Trouble:
When the compressor is stopped, the current value at the other compressor is high.
When this type of condition occurs, seizing-detection control takes priority.
Correction
(1) Replace the CT circuit.
(2) Replace the outdoor unit PCB.
(3) Correct the problem.
Example
(1) The connector was not inserted after the PCB was replaced.
Notes
Use a normal CT as a tool to determine whether the trouble is a PCB failure or CT failure.
→
H05, H15, H25 Alarm
Alarm code
H05, H15, H25
Alarm meaning
Compressor 1 discharge temperature sensor (DISCH1) disconnected; Compressor 2 discharge
temperature sensor (DISCH2) disconnected; Compressor 3 discharge temperature sensor
(DISCH3) disconnected
Alarm conditions
• This alarm occurs when the discharge sensor temperature detector is not inserted into the tubeʼs
sensor holder, or when the sensor itself has suffered some kind of malfunction other than a cut
wire.
• When outdoor air temperature is 0°C or higher:
Alarm occurs if the temperature detected by the discharge sensor has changed by less than
2 deg. when the compressor has operated for 10 minutes immediately after start.
• When outdoor air temperature is below 0°C:
Alarm occurs if the temperature detected by the discharge sensor has changed by less than
2 deg. when the compressor has operated for 30 minutes immediately after start.
Probable cause
(1) Discharge sensor temperature detector is not inserted into the tubeʼs sensor holder.
(2) Discharge sensor itself has suffered some kind of malfunction other than a cut wire.
Check
(1) Check that the discharge temperature sensor is inserted into the sensor holder.
(2) Check that sufficient heat-conducting putty is applied.
(3) Remove the discharge sensor from the sensor holder and expose the sensor to the outside
air for approximately 5 minutes. Check that the temperature detected by the sensor changes
to match the outside air temperature. (However the sensor cannot detect temperatures at or
below 0°C.)
Correction
(1) Install the sensor into the holder, and apply sufficient heat-conducting putty.
(2) If the sensor is malfunctioning, replace it.
Example
Notes
The discharge temperature sensor is generally a sensor intended for accurate detection of high
temperatures. Therefore, it will not accurately detect the temperature if the temperature at the
measurement point is 20°C or below.
