Johnson Controls York YD Manual page 49

Table 9: Safety shutdown messages
Message
THRUST BEARING #2
– PROXIMITY PROBE
CLEARANCE
THRUST BEARING #1 –
PROXIMITY PROBE OUT OF
RANGE
Model YD Mod D with OptiView Control Center
Description
The chiller (both compressors) has shutdown because the clearance between Compressor
#2 high speed thrust collar and the tip of the proximity Probe has increased > +10 mils
(instantaneous) or decreased > -25 mils (for 2 continuous seconds) from the Reference
Position. The minimum allowed clearance is 23 mils. Therefore, if the Reference Position is <
47 mils, the shutdown will occur when the actual position is < 22 mils. The chiller cannot be
started until the special reset procedure is performed as referenced in the CAUTION below.
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.
The clearance is only checked during the last 20 seconds of "System Prelube", during
"System Run" and during "Coastdown". Therefore, the fault is only detected during
those periods. Also, the +10 mil threshold must be exceeded for 2 continuous seconds
(instantaneous with previous software).
CAUTION: This shutdown must be evaluated by a qualified Service Technician prior
to starting the chiller. Starting the chiller without this evaluation could result in
severe compressor damage. To prevent the chiller from starting without the proper
evaluation, restart is inhibited until the clearance is within acceptable limits and a
special reset procedure is performed by the Service Technician. The evaluation and
reset procedure are contained in Service Manual (Form 160.69-M1-C).
The chiller (both compressors) has shutdown because the clearance between compressor
#1 high speed thrust collar and the tip of the proximity Probe has decreased to <17 mils. The
chiller cannot be started until the special reset procedure is performed as referenced in the
CAUTION below.
If compressor #1 is locked out using the Lockout key on the Capacity Compressor Cycling
Screen, this fault does not cause compressor #2 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.
The clearance is only checked during the last 20 seconds of "System Prelube", during
"System Run" and during "Coastdown". Therefore, the fault is only detected during
those periods. Also, the +10 mil threshold must be exceeded for 2 continuous seconds
(instantaneous with previous software).
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