Hitachi RPI-4.0FSN4E - Device Control System

5 Control system
182
SMGB0077 rev.0 - 01/2013
5.1 Device control system
Purpose of control
Use
Cooling operation Heating operation Defrost mode
Compressor control
frequency with Inverter
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.
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.
Fixed frequency (stop the
compressor for 30 s. once defrost
is complete).
Degree of opening of the
outdoor unit expansion
valve
Fully open
The control range for the degree
of opening of the expansion
valve is determined to optimise
the temperature at the top of the
compressor.
Fully open
Degree of opening of the
indoor unit expansion
valve
The control range for the degree
of opening of the expansion
valve is determined to optimise
the difference in temperature
of the I.U. gas pipe (Tg) - the
temperature of the I.U. liquid
piping (Tl).
Degree of opening specied
at the start of normal control.
Then controlled to optimise the
temperature of the I.U. liquid pipe
(Tl).
Specied degrees of opening
controlled by the temperature at
the top of the compressor. (Td).
Outdoor fan
The fan speed operates to
control the stabilisation of the
O.U. liquid pipe temperature
(Te); (Te) stabilisation control
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.
Fan stoppage.
4-way valve (RVR) Off On Off
Solenoid valve (SVS)
(Balanced pressure valve)
Enabled on starting (4-10)H(V)
RNSE
Enabled on starting (4-10)H(V)
RNSE
Enabled by defrost
High/low pressure balance
• Control by the indoor
expansion valve (2-3
HVRN(1)(S)
• SVA activation before the
compressor is started (4-
10)H(V)RNSE
• Control by the outdo-
or expansion valve (2-3
HVRN(1)(S)
• SVA activation before the
compressor is started (4-
10)H(V)RNSE
I.U.: indoor unit.
Tc/Te: condensing temperature / evaporating temperature.
Td: Discharge temperature.
Tl: liquid temperature.
Tg: gas temperature.
Cap: capacity.