Hitachi SAMURAI Series Service Manual page 44

2. Control Functions
Control functions on the module
2.1.16 Silence priority mode (Night shift) (Only in cooling operation)
It is possible to operate with a reduced fan noise, for instance at night. Silence priority mode becomes enabled by the input
of non-voltage contact. Therefore, it is possible to switch remotely between standard mode for the day and silence priority
mode for the night. (It is also possible to switch in the middle of operation)
For wiring
Time chart
ON
Silence priority
mode signal
OFF
Operation mode Night shift
of FAN
Standard
Silence priority mode (Night shift)
N O T E
The figure is a example, and the actual effect will vary depending on temperature conditions and operation load state.
36
SMGB0082 rev.1 - 07/2015
Control board of the chiller unit
Silence priority mode
Open: Disable
Closed: Enabled
Cooling/Heating
Switch
Operation mode
of the system
Heating
Cooling
Heating
Cooling
Effect in silence due
to the reduction of fan
revolutions: about 1dB
(COP is equivalent to
high outdoor temperature)
Standard mode
Outdoor temperature (ºC)