Daikin Altherma HT Service Manual

Troubleshooting by Indication on the Remote Controller ESIE09-08B
194 Troubleshooting
3.53 “U0 ” Low Pressure Drop Due to Refrigerant Shortage or
Electronic Expansion Valve Failure
Remote Control
Display
U0
Applicable
Models
ER*Q 011~016*
Method of
Malfunction
Detection
Short of gas malfunction is detected by discharge pipe temperature thermistor and low pressure
saturation temperature.
Malfunction
Decision
Conditions
Microcomputer judge and detect if the system is short of refrigerant.
Malfunction is not decided while the unit operation is continued.
Supposed
Causes
 Out of gas or refrigerant system clogging (incorrect piping)
 Defect of pressure sensor
 Defect of outdoor unit PC board (A1P)
 Defect of thermistor R3T

Daikin Altherma HT Specifications

General

Type	Air-to-water heat pump
Refrigerant	R-410A
Water Outlet Temperature	Up to 80°C
Operating Temperature Range	-20°C to 35°C
Power Supply	3-phase, 400V
Energy Efficiency Class (Heating)	A++