Gas Shortage Detection - Daikin Sky Air R-407C Service Manual

Error Codes: System Malfunctions
4.2 Gas Shortage Detection (U0)
1
Error code
LED indication
Error method
3 3
4
Error generation
Causes
5
Troubleshooting
3–54
U0
The table below shows the LED indication.
Operation
Normal
Malfunctioning
The discharge pipe thermistor detects the malfunction temperature at which there can be a gas
shortage. If the discharge temperature exceeds 125˚C during more than 20 s, the outdoor unit will stop
and retry when the guard timer is OFF (3 min have passed).
During the retrial, the expansion valve will be opened 90 pulses more than in case of the previous start.
When the unit restarts with a fully opened expansion valve, the remote control displays "U0" after
pressing the test button.
The error is generated when the microcomputer detects gas shortage. However, the unit can still
operate.
The possible causes are:
Refrigerant shortage
Clogging of the refrigerant piping circuit.
To troubleshoot, proceed as follows:
Check the amount of
Ÿ
Check the refrigerant piping
circuit for clogging.
Ÿ
Check the expansion valve.
Refer to error E9.
Ÿ
Check the discharge thermistor.
Refer to error F3.
HAP (green)
6
—
refrigerant.
Is it correct? No
Yes
H1P (red) H2P (red)
8 8
— —
Fill with the proper
amount of refrigerant.
Part 3 – Troubleshooting
ESIE02–01