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Table 142: Cycling shutdown messages
Message Description
Oil Pump #2 – Drive
Contacts Open
The oil pump variable speed drive for compressor 2 has shutdown the chiller (both
compressors). It initiates this shutdown by opening its status contacts connected to the I/
O Board TB3-71. The drive initiates a shutdown anytime its internal protection circuits will
not permit the drive to run. The contacts remain open until its internal protection circuits are
satisfied and any applicable manual resets are performed. Refer to YORK Variable Speed Oil
Pump Drive Service Manual 160.52-M2 .
If compressor 2 is locked out using the Lockout key on the Capacity compressor cycling
screen, this fault does not cause compressor 1 to shutdown or prevent it from starting.
When this fault occurs on a locked-out compressor, it is displayed as a warning. This allows
the user to know that a fault exists on the locked-out compressor. The condition must be
corrected prior to the lockout being removed from the compressor. If it is not, the warning
condition will revert back to a shutdown as soon as the lockout is removed and will cause the
chiller to trip.
Proximity Probe – Low
Supply Voltage
The chiller (both compressors) has shutdown because the Proximity Probe +24 VDC
supply voltage has decreased to < the required minimum of +19.0 VDC. The chiller will
automatically restart when it increases to > 19.7 VDC. When this condition occurs on a locked
out compressor (using the Lockout key on the Capacity compressor cycling screen) this fault
does not cause the other compressor to shutdown or prevent it from starting. It is displayed
as a warning. This allows the user to know that a fault exists on the locked compressor. The
condition must be corrected prior to the lockout being removed from the compressor. If it
is not, the warning condition will revert back to a cycling shutdown as soon as the lockout is
removed and will cause the chiller to trip.
Discharge #1 – Valve
Not Closed
The chiller (both compressors) has shutdown because compressor 1 discharge valve did not
fully close (as indicated by the closure of the valve closed end switch) within 40 seconds of
receiving the close command. If the chiller was running when this occurred, the pre-rotation
vanes of the running compressors are driven fully closed prior to shutting down the chiller.
The chiller will be allowed to restart when the valve closed end switch closes. The end switch
position is not considered valid until it has been in the position continuously for at least 3
seconds. This prevents the possibility of initiating a fault due to switch bounce.
Discharge #2 – Valve
Not Closed
The chiller (both compressors) has shutdown because the compressor 2 discharge valve did
not fully close (as indicated by the closure of the valve closed end switch) within 40 seconds
of receiving the close command. If the chiller was running when this occurred, the pre-
rotation vanes of the running compressors are driven fully closed prior to shutting down the
chiller. The chiller will be allowed to restart when the valve closed end switch closes. The end
switch position is not considered valid until it has been in the position continuously for at
least 3 seconds. This prevents the possibility of initiating a fault due to switch bounce.
Expansion I/O – Serial
Communications
The chiller (both compressors) has shutdown because the serial communications from the I/
O Boards to the microboard has been lost for 20 continuous seconds. The chiller can restart
when the serial communications have been restored.
Oil – Low Temperature
Differential
The chiller (both compressors) is prevented from starting for one of the following reasons.
The chiller will automatically restart when the conditions have been satisfied.
The chiller has been shut down for <30 minutes and the oil temperature minus the
condenser saturation temperature is <30°F.
OR
The chiller has been shut down for > 30 minutes and the oil temperature minus the
condenser saturation temperature is < 40°F.
OR
Following a Power failure, upon restoration of power, the oil temperature minus the
condenser saturation temperature is < 40°F.
Oil – Low Temperature The oil temperature has decreased to < 55°F. The chiller will automatically restart when the
temperature increases to > 55.0°F and is greater than the Condenser Saturated temperature
by 30 or 40°F, as described above in the Oil – Low Temperature Differential
message description.
Model YD Mod D with OptiView Control Center 138