Controller System; Controller Adjustment - Hitachi RCUE40AG1 Installation, Operation And Maintenance Instructions

CONTROLLER ADJUSTMENT

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8.1. CONTROL SYSTEM
Electrical Operation Control advanced HITACHI Water
Chillers are as follows.
"
Capacity Control
All models are equipped with an unloading system for each
compressor, in order to adjust the cooling capacity and to
provide precise temperature control for the chilled water,
coupled with electronic thermostats.
"
Control Panel
ON switch, OFF switch, Power Supply Lamp, Operation
Lamp, Alarm Lamp, Operation/Alarm Indicator for each
refrigerant cycle and check switch are mounted in the
Control Panel. The Control Panel is located at a position
where easy access is available. Operation/Alarm indicator
can display individual alarm codes such as High-Cut, Low-
Cut etc. this function is very useful for detecting what alarm
has occurred. Check switches are for checking chilled
water temperature and alarm occurrence data. Chilled
water temperature setting switches, ON/OFF Differential
Setting Switches, Remote-Local Switch and so on are
located at the rear side of Control Panel, in order not to
access during operation.
"
Operation Hour-Meter
This hour-meter indicates the sum of the compressor
operation
8.2. CONTROLLER ADJUSTMENT
Layout of control panel of printed circuit board is shown in
the Figure of the last page.
Setting functions are followings:
"
Chilled Water Outlet Temperature Setting
Switch = RSW1 and RSW2
= 7°C for chilled water outlet temperature is recommended.
The RSW1 and RSW2 dials are already set at 7 and 0.
Setting at the figures from 3 to 9 of the RSW2 dial should
not be permitted.
"
Chiller Type Set Switch = RSW5, 6, 7
Concerning of this series, RSW5 and RSW6 are used for
identification of the series.
= The RSW5 and RSW6 are already set at 9 and 9.
Setting at the figures from 0 to 8 of these dials and all of
the figures of RSW7 should not be permitted.
"
Neutral Zone Setting Switch = RSW8
= 2 degrees is standard. The RSW8 dial is already set at 3
= 2 degrees.
The figures at the RSW8 dial means as follows:
0 1 2
Figure
Band (degree) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
3 4 5 6 7 8 9
"
Printed Circuit Board
A micro-processor, relays and electronic components are
mounted on the Printed Circuit Board. Increased reliability
is assured due to the elimination of mechanical parts and
wires. This board contains various function by applying
micro-processor as follows:
Screw Compressor Cycling Protection Circuit.
The electronic timer of the screw compressor cycling
protection (ccp) connected in the compressor control circuit
delays the screw compressor restarting period for
approximately three (3) minutes for No.1 compressor, four
(4) minutes for No.2 compressor, five (5) minutes for No.3
compressor, six (6) minutes for No.4 compressor.
Electronic Thermostat Circuit.
The electronic thermostat senses chilled water outlet
temperature, and operate capacity control solenoid valves
of HITACHI screw compressor.
Screw Compressor Reversing Protection Circuit.
This circuit is composed of a reverse-phase protection
devices, preventing reverse operation of the screw
compressor, because the screw compressor definitely
cannot be operated in the wrong direction, due to the
misconnection of the main power phases
Restart after Short Period Power-Failure.
In the case that a power failure shorter than 2 seconds
occurred, compressors can be restarted automatically
within 3 minutes after power supply.
"
Continuous Capacity Control Setting Switch =
DSW5
Definition of Special Terms.
Water
Temperature
Load Up 1 Mode
Set by
DSW5,
5 pin
Load Up 2 Mode
Water Outlet
Temperature
Set by
RSW8
Neutral Zone
Setting Temperature
Set by
Load Down Mode
DSW5,
1&2 pin
Standard
Setting
10°C
Set by
9°C
DSW5,
3&4 pin
Water Inlet
Temperature
Inlet Water Temp.
when system is
stopped with
Thermos Off mode
7°C
6°C
Thermo Off