95
If the free cooling is activated the control shall take the following measure:
If chiller is in not in OFF status, ignore the free cooling request (chiller will continue to run) until chiller
shut down.
Else
Unit will be locked so the compressor cannot run
Condenser water pump output forced to ON
Evaporator water pump output forced to ON
Head Pressure valve is forced to the fully open position.
The 1st & 2nd IGV will be opened in the maximum open position
The liquid bypass valve is forced to the fully open position
The envelope stability control valve is forced to the fully open position
The economizer isolation valve is forced to be fully open position
A Digital Output “free cooling active” will be energized
The free cooling valve is forced to the fully open position (19DV only)
A message (event 9) will be displayed on the chiller control display
Chiller status shall be “FREECOOL”
5.35. Marine Option
Marine chillers are a little different from common chillers, and have a few new functions.
5.35.1. Oil Stir Function
If ”Option 2” -> ”Marine Option” is enabled, when chiller is not running, the oil pump will be switched on
for 30 seconds every 3 hours, no matter oil heater is on or off. When oir stir is in progress, oil heater will
be switched off.
5.35.2. Power Request
If ”Option 2” -> ”
Marine Pwr Req Option” is enabled, when chiller is starting up, it will send power
request signal and alert 104 while verifying water flow. After it receives the permission to start feedback,
the start up will proceed. The power request signal will remain active till the compressor is switched on. If
there is still no permission to start feedback 5 minutes after power request is sent, or permission to start
feedback is deactivated before compressor is switched on, the start up process will terminate and trigger
an alarm.
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