Panasonic CU-E18CKR Service Manual page 29

8.1.10.2. Quiet operation (Heating)
A. Purpose
To provide quiet heating operation compare to normal operation.
B. Control condition
a. Quiet operation start condition
- When "quiet" button at remote control is pressed.
Quiet LED illuminates.
b. Quiet operation stop condition
1. When one of the following conditions is satisfied, quiet operation
stops:
A. Powerful button is pressed.
B. Stop by OFF/ON switch.
C. Timer "off" activates.
D. When change mode to fan only mode.
E. Quiet button is pressed again.
2. When quiet operation is stopped, operation is shifted to normal
operation with previous setting.
3. When fan speed is changed, quiet operation is shifted to quiet
operation of the new fan speed.
4. When operation mode is changed, quiet operation is shifted to
quiet operation of the new mode, except fan only mode.
5. During quiet operation, if timer "on" activates, quiet operation
maintains.
6. After off, when on back, quiet operation is not memorised.
C. Control contents
a. Fan Speed manual
1. Fan speed is changed from normal setting to quiet setting of
respective fan speed.
This is to reduce sound of Hi, Me, Lo for 3dB.