143
Device control system
SMGB0066 rev.0 - 12/2009
Controller pack
Service Manual
4
Using the special functions
•
HOLIDAY Function
The holiday function allows you to set a constant temperature (default = 10°C) for a specified number of days (from 1 - 99
days). This lets you save energy and related costs when you are away from home, but resumes normal operation on the day
of your return.
To set the Holiday function:
Ensure the Hitachi room unit is running in AUTO (
a.
) or MAN (
) operating modes.
Press the holiday button to display the holiday
b.
days counter and temperature setting, along with the holiday
indicator
.
Press the
c.
or
time buttons to set the holiday time (1 to 99 days) and press the green
button to confirm.
Press the
d.
or
buttons to set the holiday temperature (5°C to 35°C) and press the green
button to
confirm.
The Hitachi room unit will now control to the new temperature for the set number of days that your home is vacant. At
midnight the holiday counter will be reduced by one until the selected number of days have passed. The Hitachi room unit
will then return to normal operation as set by the AUTO (
) or MAN (
) mode. To cancel the HOLIDAY function or to exit
the function at any time press the
button a second time.
Adjusting the time
•
To adjust only the time during normal operation use the
or
buttons to adjust the time and press the green
button again to confirm any changes.
4.23. dEVICE ConTrol SySTEM
Control subject
Purpose
Heating operation
defrost operation
Control frequency of
inverter compressor
The frequency control is determined by PI
control, through the next parameters:
∆ outlet temperature and water target
temperature.
Fixed frequency
Opening degree expansion
valve for main circuit
- Control range of expansion valve
opening degree is determined to
optimize TsSH.
Fully open
Opening degree expansion
valve for liquid injection
- Specified opening degree controlled by
temp. on the top of compressor (Td.).
-
Fan
- Fan Step is controlled according to PS
(Suction pressure)
Fan stop.
4-Way valve (RVR)
ON
OFF
Solenoid valve (SVG)
(Hot gas bypass)
- Turn ON at starting before 4-way valve
ON.
Turn ON for 1 minute
at defrosting
Solenoid valve (SVI)
(Liquid injection)
-
Turn ON if Td≥90ºC continue 3 seconds
OFF
Temp.:Temperature
Td: discharge temperature
TsSH: Suction gas super heat
Ps: suction pressure
