Troubleshooting for RA Indoor Unit
SiBE121123_A
165
Service Diagnosis
5.4
Radiant Panel Temperature Rise, Indoor Electronic
Expansion Valve (Motor Operated Valve) Abnormality,
Freeze-up Protection Control (FVXG Series Only)
Error Code
A9
Method of Error
Detection
Radiant panel temperature rise
During RADIANT operation, high temperature control (e.g., operation halt, indoor electronic
expansion valve closure) is activated according to the temperature detected by the radiant
panel thermistors.
Indoor electronic expansion valve abnormality
The indoor electronic expansion valve is required to be fully closed during cooling, dry or
heating operation. When the indoor electronic expansion valve is open due to malfunction,
the refrigerant flows into the radiant panel and the radiant panel temperature rises or drops.
The indoor electronic expansion valve is required to be open during RADIANT operation.
When the indoor electronic expansion valve is closed due to malfunction, the refrigerant
does not flow into the radiant panel and the radiant panel temperature does not rise.
For multi system
The indoor electronic expansion valve is required to be fully closed in the room where the
system does not run. When the indoor electronic expansion valve is open due to malfunction
and heating or RADIANT operation is conducted in the other room(s), the refrigerant flows
into the radiant panel and the radiant panel temperature rises.
Freeze-up protection control
The temperature detected by the radiant panel thermistors is used to prevent the indoor unit
from freezing during cooling operation.
Error Decision
Conditions
Radiant panel temperature rise
The radiant panel surface temperature calculated by the radiant panel thermistors is above
70°C.
Indoor electronic expansion valve abnormality
During cooling or dry operation, the temperature detected by the radiant panel thermistor
(
φ
4) has dropped.
During heating operation, the temperature detected by the radiant panel thermistor (
φ
4) has
risen.
During RADIANT operation, the temperature detected by the radiant panel thermistor (
φ
4)
does not rise.
For multi system
While the system does not run and heating or RADIANT operation is conducted in the other
room(s), the temperature detected by the radiant panel thermistor (
φ
4) has risen.
Freeze-up protection control
During cooling operation, the operation stops when the temperature detected by the radiant
panel thermistor (
φ
4) has dropped.
Supposed
Causes
Clogged air filter of the indoor unit
Dust accumulation on the indoor heat exchanger
Short-circuited air
Defective radiant panel thermistor(s)
Defective indoor heat exchanger thermistor
Defective room temperature thermistor
Defective indoor electronic expansion valve (or coil)
