Flooded type water cooled screw chiller (MIC)
MCAC-CTSM-2018-1
114
12)
loss of cooler water flow
13)
loss of condenser water flow
14)
starter fault
b. The control system shall detect conditions that approach protective limits and take
self-corrective action prior to an alarm occurring. The system shall automatically reduce chiller
capacity when any of the following parameters are outside their normal operating range:
1) high condenser pressure
2) high motor temperature
3) low evaporator refrigerant temperature
4) high motor amps.
c. During the capacity override period, a pre-alarm (alert) message shall be displayed informing
the operator which condition is causing the capacity override. Once the condition is again
within acceptable limits, the override condition shall be terminated and the chiller shall revert
to normal chilled water control.
3. Multiple Chiller Control:
The chiller controls shall be supplied as standard with a two-chiller lead/lag and a third chiller
standby system. The control system shall automatically start and stop a lag or second chiller on a
two-chiller system. If one of the two chillers on line goes into a fault mode, the third standby chiller
shall be automatically started. The two-chiller lead/lag system shall allow manual rotation of the
lead chiller, include load balancing if configured, and a staggered restart of the chillers after a
power failure.
I. Vibration Isolation:
Chiller manufacturer shall furnish spring isolators for mounting equipment on a level concrete surface.
J. Special Features:
Automatic Hot Gas Bypass:
1. BACnet Communication:
Shall provide field-installed communication capability with a BACnet network.