Johnson Controls York YCIV A Series User Manual

JOHNSON CONTROLS
243
SECTION 8 - MICROPANEL
FORM 201.23-NM2
ISSUE DATE: 3/9/2015
8
UNIT SAFETIES
Unit Safety Operation
Unit faults are safeties that cause all running compres-
sors to be shut down, if a safety threshold is exceeded
for 3 seconds. Unit faults are recorded in the history
buffer along with all data on the unit and system oper-
ating conditions. Unit faults are auto reset faults where
the unit will be allowed to restart automatically after
the fault condition is no longer present. The only ex-
ception is any of the VSD related unit faults. If any 3
VSD unit faults occur within 90 minutes, the unit will
be locked out on the last fault. A VSD lockout condi-
tion requires a manual reset using the system switches.
Both system switches must be cycled off and on to
clear a VSD unit lockout fault. If a unit safety is in
effect, the message will be displayed to the operator
when the STATUS key is pressed.
LD10605
STATUS
KEY
In the descriptions of the fault displays that follow, the
fault message will show a YYYYYYY to indicate that
a system is in a “FAULT” condition and will restart
when the fault clears or LOCKOUT” and will not re-
start until the operator clears the fault using the keypad.
If a control panel safety occurs after the VSD fault, but
before the fault is reset, the control panel fault is an
ALL FAULT of the VSD fault, meaning it will be reg-
istered as such in the History because it occurred while
the VSD was shutting down or while the systems were
shut down. All faults do not store operating data at the
time of the fault.
If a “VSD” fault occurs during the fault rampdown or
while the systems are shut down, the VSD fault will
be registered as a new fault. The reason for this is the
belief any VSD fault should be registered with a full
account of the systems data at the time of the fault.
High Ambient Temp Fault
If the ambient temperature rises above 130 F, the chill-
er will shut down with a controlled ramped shutdown.
Restart will automatically occur, if demand allows,
when temperature falls 2°F below the cutout (128°F).
This fault cannot cause a lockout. The fault display
message will be present only during the time when
the ambient temperature is causing a fault condition. A
sample display is shown below:
UNIT YYYYYYYY
HIGH AMBIENT TEMP
The unit will also be inhibited from starting any time
the temperature is above 128°F.
Low Ambient Temp Fault
If the ambient temperature falls below the program-
mable Low Ambient Temp Cutout the chiller will shut
down with a controlled ramped shutdown. This fault
will only occur if the Low Ambient Cutout is “EN-
ABLED” under the OPTIONS key. Restart can occur,
if demand allows, when temperature rises 2°F above
the cutout. This fault cannot cause a lockout. The fault
display message will be present only during the time
when the ambient temperature is causing a fault condi-
tion. A sample display is shown below:
UNIT YYYYYYYY
LOW AMBIENT TEMP
The unit is also inhibited from starting any time the
temperature is below the cutout plus 2°F.
Low Leaving Chilled Liquid Temp Fault
The Low Leaving Chilled Liquid Temp Cutout helps to
protect the chiller from an evaporator freeze-up should
the chilled liquid temp drop below the freeze point.
This situation could occur under low flow conditions
or if the Micro Panel setpoint values are improperly
programmed. Any time the leaving chilled liquid tem-
perature (water or brine) drops below the program-
mable cutout point, the chiller will fault and shutdown
with a controlled ramped shutdown. Restart can occur,
if demand allows, when chilled liquid temperature
rises 4°F above the cutout. This fault cannot cause a
lockout. A sample shutdown message is shown below:

Johnson Controls York YCIV A Series Specifications

General

Brand	Johnson Controls
Model	York YCIV A Series
Category	Chiller
Language	English