Product data

Guide specifications (cont)
one year in advance (month, day, and dura-
tionofdays).Display of the occupancy sched-
ules shall be viewable on the LCD screen.
Each schedule shall provide a means of con-
figuring an occupancy time override to per-
mit a ‘‘one time extension’’ of an occupied
period on the configured day. The controls
shall also provide for chiller start-up and shut-
down through a remote contact closure from
a customer supplied device or from a build-
ing management system software command.
SETPOINT FUNCTION
The controls shall provide the capability to
view and change the leaving chilled water set
point, entering chilled water set point, de-
mand limit set point, or ice build set point at
any time during chiller operation or shut-
downperiods.Thecontrols shall allow for the
specification of capability control through ei-
ther leaving chilled water or entering chilled
water.
SERVICE FUNCTION
The controls shall provide a password pro-
tected service function which allows autho-
rized individuals to:
• View the alarm history file which contains
the last 25 alarm/alert messages with time
and date stamp. These messages shall be
displayed in text form, not in codes.
• Execute the chiller Control Test function
for quick identification of malfunctioning
components
• View, modify, and/or configure systems
and controls options, capacity and safety
override limits and parameters.
• View/modify chiller occupancy periods
• View/modify schedule holiday periods
• View/modify schedule override periods
• View/modify system time and date
• Specify a network address
• Change units display on the LID
2. Safeties:
a. Unit shall automatically shut down when any
of the following conditions occurs (Each of
these protective limits shall require manual
reset and cause an alarm message to be dis-
played on the LCD screen informing the op-
erator of the shutdown cause.):
1) Motor overcurrent
2) Over voltage*
3) Under voltage*
4) Single cycle dropout*
5) Low evaporator refrigerant temperature
6) High condenser pressure
7) High motor temperature
8) Highcompressordischarge temperature
9) Low oil pressure
10) Low oil level
11) Loss of cooler water flow
12) Loss of condenser water flow
13) Starter fault
14) High oil filter differential pressure
15) Low discharge superheat temperature
(Frame 1 and 2 chillers)
16) Out-of-range sensors
17) Excessive starter transition time
18) Motor current signal loss
19) Motor power supply phase reversal
20) Temperaturesensorand transducer faults
21) Single cycle dropout
22) Motor running in reverse (miswired)
23) Motor running without control
authorization
*Will not require manual reset or cause an
alarm if auto-restart after power failure is
enabled.
b. Thecontrolsystem shall detect conditionsthat
approach protective limits and shall take self-
corrective action prior to an alarm occurring.
The system shall automatically reduce chiller
capacity when any of the following are out
of normal operating range:
• High condenser pressure
• High motor temperature
• Low evaporator refrigerant temperature
• High motor amps
During the capacity override period, a pre-
alarm (alert) message shall be displayed in-
forming the operatorwhichconditioniscaus-
ing the capacity override. Once the condition
is again within acceptable limits, the override
condition shall terminate and the chiller shall
revert to normal chilled water control. If dur-
ing either condition the protective limit is
reached, the chiller will shut down, an alarm
shall be generated, and a text message will
be displayed informing the operator which
condition caused the shutdown and alarm.
3. Diagnostics and Service:
a. The control system shall execute a series of
pre-start checks whenever a start command
is received to determine if pressures, tem-
peratures, and timers are within pre-start lim-
its, thereby allowing start-up to proceed. If
any of the limits are exceeded, a text alert
message will be displayed informing the op-
erator of the cause of the pre-start alert.
b. A self-diagnostic control test shall be an in-
tegralpart of the control systemto allow quick
identification of abnormal system conditions
andmalfunctioning chiller components. Once
the controls test has been initiated, all pres-
sureand temperaturesensors shall bechecked
to ensure they are within their normal oper-
ating range. A pump test shall automatically
energize the chilled water and condenser wa-
ter pumps. The control system shall confirm
that water flows have been established and
require operator confirmation prior to pro-
ceeding to the next test.
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