U0" Gas Shortage (Malfunction) - Daikin SkyAir Service Manual

Troubleshooting by Remote Controller Display / LED Display

5.37 "U0" Gas Shortage (Malfunction)

U0
Remote
Controller
Display
Applicable RZQ71~140C7V1B, RZQS71~140C7V1B
Models
Method of (In cooling operation)
Detection based on difference in temperature between temperature preset by remote controller
Malfunction
and indoor suction air temperature, motorized valve opening degree, compressor frequency and
Detection
low pressure.
(In heating operation)
Detection based on difference in temperature between temperature preset by remote controller
and indoor suction air temperature, motorized valve opening degree during the control of
suction air superheating, high pressure, indoor heat exchanger temperature and indoor suction
air temperature.
Malfunction (In cooling operation)
Decision When compressor frequency does not increase even though the load is heavy because the
motorized valve is opened to the fullest extent
Conditions
[If low pressure drops when the compressor is at 41Hz, malfunction is confirmed.]
(In heating operation)
When suction gas superheat degree is large, compressor frequency is low and the motorized
valve is opened to the fullest extent even though heating load is heavy
[If high pressure is lower than saturated pressure for indoor heat exchanger temperature (or
indoor suction air temperature), malfunction is confirmed.]
Supposed
Causes
212
Refrigerant shortage (out of gas)
Clogged refrigerant piping system
Mismatching of wiring and piping
SiBE28-804
Troubleshooting