York YCIV Series, Installation Operation & Maintenance

Page: 234 / 326

JOHNSON CONTROLS
234
FORM 201.23-NM2
ISSUE DATE: 09/25/2020
SECTION 8 - MICROPANEL
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:
UNIT YYYYYYYY
LOW LEAVING CHILLED LIQUID TEMP
The unit is inhibited from starting any time the chilled
liquid temperature is below the cutout plus 4°F.
VSD Communications Failure Fault
The VSD Communications Failure is to prevent the
unit from trying to run, if the Chiller Control Board
never initializes communications with the VSD Logic
Board. The unit will also shut down with a controlled
ramped shutdown if the Chiller Control Board loses
communications with the VSD Logic Board while the
chiller is operating.
On power-up, the Chiller Microprocessor Board will
attempt to initialize communications with the VSD
Logic Board. The control panel will request data from
the VSD, which includes the number of compressors
and the VSD software version. Once these data points
have been received by the Chiller Control Board, and
have been successfully initialized, the Chiller Control
Board will not request them again. If the comms con-
nection fails to occur, the Chiller Control Board will
prevent the chiller from operating and a fault message
will be displayed.
During normal operation, if the control panel Chiller
Control Board receives no valid response to messages
for 8 seconds, the unit will shut down all compressors
on a Comms fault. The Chiller Control Board will con-
tinue to send messages to the VSD while faulted. The
unit will be inhibited from starting until communica-
tions is established. The fault will automatically reset
when the Chiller Control Board receives a valid re-
sponse from the VSD for a data request. Shown below
is an example of a Comms Failure fault message:
UNIT YYYYYYYY
VSD COMMUNICATIONS FAILURE