Hitachi SAMURAI Series Service Manual page 14

2. Control Functions
Control functions on the module
Item
Anti-freezing for In order to prevent freezing caused by a decrease of water temperature in winter or under other low ambient
winter temperature conditions, pump operation order is output automatically.
(Automatic pump
operation)
N O T E
Starting conditions can be selected locally from the 3 types below.
•
Water temperature under 15ºC (mainly for systems where the total pump head from the chiller unit to the load
side is supported by a common pump. It protects the entire chiller and load side equipment)
•
Water temperature under 5ºC (mainly for systems where the head of chiller unit side and of load side are
supported by separate pumps). It only protects the chiller unit side)
•
Disable function: When selecting "Disable function", other freeze prevention measures, such as extraction
of water in winter or winding a heater around the heat exchanger are necessary. Refrigerant may leak if the
water side heat exchanger freezes.
It is not possible to switch between remote and main unit control during operation of the chiller unit. An alarm
Incorrect operation
is output with respect to such incorrect operation, and to wrong DIP switch settings. Also, an alarm is output to
prevention
prevent danger, in case that an operation order is input from a remote when settings are for main unit control.
Compressor operation can be limited by external signal input.
Forced thermo OFF: Compressor is stopped forcedly during external signal input.
Current limit function: Operation capacity is limited to make the running current lower than the setting value of
Demand control
current limit control, during external signal input. Limit value can be changed by local settings.
Forced load-up: Load-up output is conducted forcedly during external signal input.
Capacity hold: Capacity control is ignored forcedly during external signal input.
Cooling operation have 2 setting temperatures each, and it is possible to select which setting temperature is
2 temperature
valid by external signal input. In case of operating with a different extraction temperature, such as heat storage
setting
or air conditioning, it is not necessary to change the setting temperature of the main chiller unit.
Forced load up is conducted during outdoor order (non-voltage a contact) input.
Forced load up from It is possible to select whether "the pump shall stop" or "the pump can be kept working" in the event of a thermo
external contact OFF, when thermo OFF judgement at the main unit is enabled.
(This function cannot be used when the function to control the number of units is used )
Information about Compressor operation time for preventive maintenance is monitored, and when it reaches the overhaul period,
overhaul period the "Overhaul mark" is shown on the LCD screen.
It is possible to disable the release of alarms by remote stop order input.
Disabling of remote
N O T E
stop alarm clear
•
Normally, alarms can be released by stop control from either remote or the main unit.
(Option)
•
Since this function is optional, it is necessary to make the settings for the enabling of this function at the time
of local installation.
It is possible to determine pump interlock abnormality and output an alarm in case that no pump feedback
signal is input after a certain amount of time has passed upon startup of the chiller unit.
Limit of waiting time
This time can be changed by local settings, between 1 and 30 minutes (in 1 minute steps).
for pump feedback
(Option)
N O T E
The default feedback waiting time is "unlimited".
It is possible to delay the judgement time of thermo OFF to avoid immediate thermo OFF when water
temperature reached thermo OFF judgement value due to fluctuations in the amount of cold water flow, caused
by momentary variations in load or the activation of valves, etc.
Thermo OFF
judgement delay
N O T E
(Option)
•
Since this function is optional, it is necessary to make the settings for the enabling of this function at the time
of local installation.
•
Thermo OFF is produced when reaching operation limit temperature, even if being in judgement time.
7
SMGB0097 rev.0 - 07/2015
Description
2