Daikin Altherma HT Service Manual

Troubleshooting by Indication on the Remote Controller ESIE09-08B
198 Troubleshooting
3.55 “U2 ” Power Supply Insufficient or Instantaneous Failure
Remote Control
Display
U2
Subcode 20: high/low voltage problem
Subcode 21: converter problem
Applicable
Models
All indoor units
Method of
Malfunction
Detection
Detection of voltage of main circuit capacitor built in the inverter and power supply voltage.
Malfunction
Decision
Conditions
When the abnormal voltage of main circuit capacitor built in the inverter and abnormal power
supply voltage are detected.
Supposed
Causes
 Power supply insufficient
 Instantaneous power failure
 Defect of indoor inverter PC board [A4P (1
ø) or A5P (3ø)]
 Converting problem
Warning: CAPACITOR SHOCK HAZARD. The capacitors (top surfaces) can hold up to
220V. Use correct precautions when servicing.

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++