American Standard CH530 - Manual (Page 55)

55 CDHF-SVU01C-EN
Head Relief Request Output
When the chiller is running in
Condenser Limit Mode or in Surge
Mode, the head relief request relay
on the 1A9–J2-6 to J2-4 will be
energized (1 minute default) and can
be used to control or signal for a
reduction in the entering condenser
water temperature. Designed to
prevent high refrigerant pressure trip-
outs during critical periods of chiller
operation.
If the unit is not equipped with the
CDPR Enhanced Condenser Limit
Option the unit will use the
condenser refrigerant temperature
sensor (input converted to saturated
refrigerant pressure) to perform the
Standard Condenser Limit function,
without the head relief request relay,
by limiting inlet guide vane stroke
and chiller capacity.
Keep in mind that Condenser Limit
Control supplements the protection
provided by the condenser pressure
high pressure cutout switch 3S1.
Motor Temperature sensor module
The motor temperature module 1A26
connects via unit wiring to the three
motor winding temperature sensors.
This module is located in the control
panel where the module is connected
to the IPC bus.
Default status relay selections are
shown. Selections can be altered
using service tool. Other choices are:
Circuit 1 Running, Circuit 2 Running,
Chiller Alarm, Circuit 1 Alarm, Circuit
2 Alarm, and Purge Alarm.
Maximum Capacity Relay
When the chiller has been operating
at maximum capacity for 10 minutes
(TechView adjustable) this relay will
activate. Also upon being less than
maximum capacity for 10 minutes
this relay will deactivate.
Compressor Running Relay
Relay activates while compressor is
running.
Machine Shutdown Manual
Reset (MMR)
Limit warning machine shutdown
auto reset relays will activate with
such conditions for remote status
indication.
Control System
Components
OPST Operation Status Option
Relay output modules 1A8 and 1A9 provide relay defaults shown (For other selections, see Installation Manual):
1A8 Optional Quad Relay
OPST Relay #1 Chiller Non-Latching Alarm J2-1 NO, J2-2 NC,
Output Status J2-3 common
1A8 Optional Quad Relay OPST Relay #2 Chiller Limit J2-4 NO, J2-5 NC,
Output Status Mode Indicator J2-6 common
1A8 Optional Quad Relay OPST Relay #3 Chiller Latching J2-7 NO, J2-8 NC,
Output Status Alarm Indicator J2-9 common
1A8 Optional Quad Relay OPST Relay #4 Chiller Running Indicator J2-10 NO, J2-11 NC,
Output Status J2-12 common
1A9 Optional Quad Relay OPST Relay #1 Chiller Maximum Capacity J2-1 NO, J2-2 NC,
Output Status J2-3 common
1A9 Optional Quad Relay OPST Relay #2 Chiller Head J2-4 NO, J2-5 NC,
Output Status Relief Request J2-6 common
1A9 Optional Quad Relay OPST Relay #3 Circuit 2 J2-4 NO, J2-5 NC
Output Status Purge Alarm to J2-6 common
1A9 Optional Quad Relay OPST Relay #4 Circuit 1 J2-1 NO, J2-2 NC,
Output Status Purge Alarm to J2-3 common
Chilled and Condenser Water
Flow Interlock Circuits
Proof of chilled water flow for the
evaporator is made by the closure of
flow switch 5S1 and the closure of
auxiliary contacts 5K1 on terminals
1X1-5 and 1A6-J3-2. Proof of
condenser water flow for the
condenser is made by the closure of
flow switch 5S2 and the closure of auxiliary contacts 5K2 on terminals
1X1-6 and 1A6-J2-2.