Specifications

Troubleshooting by Indication on the Remote Controller SiUS39-601
178 Troubleshooting
2.45 “U4” Malfunction of Transmission Between Indoor Units
and Outdoor Units
Remote
Controller
Display
U4
Applicable
Models
All model of indoor unit
RXYQ72M, 96M
Method of
Malfunction
Detection
Microcomputer checks if transmission between indoor and outdoor units is normal.
Malfunction
Decision
Conditions
When transmission is not carried out normally for a certain amount of time
Supposed
Causes

Indoor to outdoor, outdoor to outdoor transmission wiring F1, F2 disconnection, short circuit or
wrong wiring

Outdoor unit power supply is OFF

System address doesn’t match

Defect of indoor unit PC board

Defect of outdoor unit PC board