Compressor Control - Hitachi SAMURAI Series Service Manual

2. Control Functions
Control functions on the module

2.1.3 Compressor Control

1 Startup control
The chiller unit receives an operation order, the cool water pump starts up, and after interlock is complete and
compressor delay time (initial setting: 0.5 minutes) has passed, compressor is started up. In continuous control type,
startup takes place in a state in which the slide valve is moved to the smallest load position.
Compressor delay time can be adjusted. change the setting value to one which is adequate for the local facilities, to
avoid compressor startup before ensuring a sufficient cold water flow.
2 Normal
Operation is performed with the smallest load for 1 minute after compressor startup.
After finishing startup control, control is shifted to normal water temperature control.
3 Stop
a. At Themo OFF
Continuous control type stops suddenly. At this time, the compressor sounds as if it was counter-rotating, due to the
pressure differential between high and low pressure.
b. Upon alarm (including retry) · momentary power failure · reception of stop order
Stops suddenly. At this time, the compressor sounds as if it was counter-rotating, due to the pressure differential
between high and low pressure.
Time chart
Compressor
operation
13
SMGB0097 rev.0 - 07/2015
ON (Chiller reception)
Operation
order
Fulfilled
Pump
interlock
Count start
Compressor delay
Delay time setting
time count
Count up
Start up control (1 minute)
Shift to normal control
2