Daikin RZQ100B8V3B Service Manual page 240

Error Codes: Outdoor Units
3.22 Gas Shortage (Malfunction) (U0)
1
Remote Controller
Display
Method of
Malfunction
Detection
3 3
Malfunction
Decision
Conditions
4
Supposed Causes
5
Troubleshooting
Caution
3–92
U0
(In test operation)
Detection by closed stop valve.
(In normal operation)
Gas shortage is detected according to the electronic expansion valve opening degree and measured
temperatures and pressures.
(In test operation)
Variations of the indoor unit heat exchange temperature judge whether stop valve is open or closed.
(In cooling operation)
When the electronic expansion valve opens fully and low pressure is below 0.1 MPa continuously for
30 minutes.
(In heating operation)
When the electronic expansion valve opens fully and the suction superheat is large (more than 20°C)
continuously for 30 minutes.
The stop valve is left in closed.
Insufficient refrigerant amount
Clogged refrigerant piping system
Is the stop valve open?
YES
Is the
refrigerant amount
appropriate?
YES
∗ For RZQ71 ~ 140 models, gas shortage alarm is indicated but operation continues.
Be sure to turn off power switch before connect or disconnect connector, or parts damage may be
occurred.
NO
Open the stop valve.
NO
Collect refrigerant. After vacuum drying is
complete, charge an appropriate amount of
refrigerant.
Check 5.9.1
Check the refrigerant piping system for clogging.
ESIE05-03
Part 3 – Troubleshooting