York YK Style H Operation Manual page 169

FORM 160.76-O2
issue date: 6/15/2015
tended Run period. This period begins when the Surge
Window Count exceeds the Count Limit. During this
period, the Pre-rotation Vanes are driven closed. When
10 minutes have elapsed, this message and the Pre-
rotation Vanes load inhibit are automatically cleared.
Message and load inhibit are also cleared when the
chiller is shutdown.
If the optional Hot Gas Bypass feature
is enabled, the valve position must be at
100% before the Extended Run is imple-
mented. If the chiller is chiller is equipped
with a Compressor Motor Variable Speed
Drive, the output frequency must be at full
speed (50Hz/60Hz) before this control can
be implemented.
Warning – Condenser Or VGD Sensor Failure
The difference between the Stall Pressure transducer
output and the Condenser Pressure transducer output
has exceeded 0.28VDC for 3 continuous minutes while
the chiller was running. This feature verifies the opera-
tion of the Stall transducer and the Condenser trans-
ducer. Since both transducers are measuring essentially
the same pressure, both outputs should be within the
specified tolerance. This message must be manually
cleared. It will be displayed until the transducer out-
puts are within the acceptable range of each other and
the WARNING RESET key in SERVICE access level.
While this message is displayed, the Variable Geom-
etry Diffuser (VGD) is driven to the full open position
and held there until this warning is manually cleared.
When cleared, the VGD returns normal operation.
Warning – Loss of Subcooler Liquid Seal
This Warning is displayed if the chiller has been run-
ning for 30 minutes or more and the Subcooler Effec-
tiveness is out of the acceptable range defined by the
Subcooler Effectiveness High and Low settings contin-
uously for 2 minutes. Subcooler Effectiveness is calcu-
lated as (Cond Sat Temp - Drop Leg Ref Temp)/(Cond
Sat Temp - Ent Cond Liq Temp). Setting the Drop Leg
Sensor Installed parameter to Disabled prevents this
warning from being displayed.
Warning – Conditions Override VGD
An extreme stall condition has been detected while the
chiller was running. An extreme stall condition exists
when the Stall Detector Voltage (output of the Stall De-
tector Board) exceeds twice the High Limit setpoint for
the duration programmed in the Extreme Stall Dura-
tion Setpoint (10 to 20 minutes). While this message is
displayed, the compressor Variable Geometry Diffuser
JOHNSON CONTROLS
SECTION 3 - DISPLAY MESSAGES
(VGD) is driven to the full open position and held there
until the message is manually cleared. This protects the
VGD ring from possible damage from an extreme stall
condition. This message can be cleared after the Stall
Detector Voltage returns to less than two times the
High Limit Setpoint and the WARNING RESET key is
pressed in SERVICE access level.
The extreme stall condition is not checked under the
following conditions:
• While the VGD is in manual control mode.
• While the VGD is fully closed (VGD Limit
Switch closed).
• While the Pre-rotation Vanes position is greater
than the PRV VGD INHIBIT Setpoint.
Warning – Motor Bearing Lube Suggested
The Operating Hours Since Last Motor Lubrication has
exceeded 1000 hours. This will be displayed until man-
ually cleared by the Operator or the Operating Hours
Since Last Motor Lubrication exceed 1200 hours,
whereupon it is replaced by the message WARNING
– MOTOR BEARING LUBE REQUIRED below. The
Operator clears this message by entering his/her ini-
tials, name or user ID in OPERATOR access level (or
higher) using the MOTOR LUBE ACKNOWLEDGE
key on the MOTOR LUBRICATION Screen. Refer to
the Motor Lubrication Screen on Page 107 for entry
instructions. The date and time of this entry is automati-
cally logged as the Date Of Last Motor Lubrication and
Time Of Last Motor Lubrication. It also resets the Op-
erating Hours Since Last Lubrication to zero. The date
this warning occurs is stored as the Date Of Last Motor
Lubrication Warning Or Fault. This warning message
will not be displayed if the Auto Lube Setpoint on the
MOTOR LUBRICATION Screen enabled.
Warning – Motor Bearing Lube Required
The Operating Hours Since Last Motor Lubrication has
exceeded 1200 hours. This replaces WARNING – MO-
TOR BEARING LUBE SUGGESTED above. This is
displayed until manually cleared by the Operator or the
Operating Hours Since Last Motor Lubrication exceed
1400 hours, whereupon it is replaced by the message
Motor – Lack Of Bearing Lubrication below. The Op-
erator clears this message by entering his/her initials,
name or user ID in OPERATOR access level (or high-
er) using the MOTOR LUBE ACKNOWLEDGE key
on the MOTOR LUBRICATION Screen. Refer to the
Motor Lubrication Screen on Page 107 for entry in-
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