Device Control System - Hitachi RCI Service Manual

5 Control system

5.1 Device control system

Purpose of control
Frequency control is determined with
the following parameters:
•
Compressor control frequency
with Inverter
•
Degree of opening of the
outdoor unit expansion valve
The control range for the degree of
opening of the expansion valve is
Degree of opening of the determined to optimise the difference
indoor unit expansion valve in temperature of the I.U. gas pipe
(Tg) - the temperature of the I.U.
liquid piping (Tl).
The fan speed operates to control the
stabilisation of the O.U. liquid pipe
Outdoor fan
temperature (Te); (Te) stabilisation
control
4-way valve (RVR)
Solenoid valve (SVS) Enabled
(Balanced pressure valve) (4-10)H(V)RNSE
•
High/low pressure balance •
I.U.: indoor unit.
Tc/Te: condensing temperature / evaporating temperature.
Td: Discharge temperature.
Tl: liquid temperature.
Tg: gas temperature.
Cap: capacity.
160
SMGB0063 rev. 1 - 10/2010
Cooling operation
Difference between the air inlet
temperature and the set air
temperature.
Calculate the width of the
change using the amount of the
change.
Fully open
Off
on starting
Control by the indoor expansion
valve (2-3 HVRN(1)(S)
SVA activation before the
compressor is started
(4-10)H(V)RNSE
Use
Heating operation
Frequency control is determined with
the following parameters:
• Difference between the air inlet
temperature and the set air
temperature.
• Calculate the width of the change
using the amount of the change.
The control range for the degree of
opening of the expansion valve is
determined to optimise
temperature at the top of
compressor.
Degree of opening specified at the
start of normal control. Then
controlled to optimise the temperature
of the I.U. liquid pipe (Tl).
The fan speed is controlled in line with
the temperature of the O.U. liquid pipe
and the temperature at the top of the
compressor.
On
Enabled on starting (4-10)H(V)RNSE
• Control by the outdoor expansion
valve (2-3 HVRN(1)(S)
• SVA activation before
compressor is started
(4-10)H(V)RNSE
Defrost mode
Fixed frequency (stop the compressor
for 30 s. once defrost is complete).
the Fully open
the
Specified degrees of
controlled by the temperature at the
top of the compressor. (Td).
Fan stoppage.
Off
Enabled by defrost
the
opening