Water Control - Hitachi SAMURAI Series Service Manual

2. Control Functions
Control functions on the module

2.1.1 Water control

Outlet water temperature of Chiller Unit is detected by Thermistor, and based on this value, compressor ON/OFF and the
most suitable capacity is determined. Following shown the continuous capacity control and change of water temperature.
Starting setting
(example)
Outlet
Tsc : 7ºC
temperature
T1: 1ºC
T2: 2ºC
T3: 2ºC
T4: 1ºC
Tsc+ T2/3+ T4
9ºC
T4
Tsc+ T2/3
8ºC
Tsc (setting t.)
7ºC
T3
(0.5~5.0ºC)
Tsc- T2/3
6ºC
T1
Tsc- T2/3- T1
5ºC
Load up I
status

Method of outlet temperature detection
1 Load-up I control at over 9°C (The capacity is changed a lot in order to approximate the target temp. quickly)
2 Load-up II control at 8~9°C (The capacity is changed moderately)
3 In neutral zone (6~8°C), load is balanced and performance is not changed.
4 Under neutral zone (below 6°C) load-down control is performed and performance is decreased.
5 Stop temp: Compressor is stopped at 5°C. The inlet temp of that time is saved.
6 When inlet temp becomes 2°C higher than that of at stop, re-start signal is output and unit is re-started after at least 3
min guard.
9
SMGB0097 rev.0 - 07/2015
Inlet
temperature
T4 (1.0~3.0ºC)
T3
T1
(0.5~2.0ºC)
Load up II
Neutral status
status
Memorizes the inlet temperature
at Thermo-OFF and re-start at
∆T2
T2
(1.0~4.0ºC)
T2
Stop
Neutral
Load-down status
status
status
Stop Start
(Thermo off)
(re-start)
Load up I zone
Load up II zone
Neutral zone
Load Down zone
Thermo-off zone
Load up II
Neutral status
status
2