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Proximity Probe
The following applies to all applications except "P"
compressors and style F and later chillers with "G"
or "H5-8" compressors. For chillers equipped with "P"
compressors, refer to Sec tion 13A: The Prox im i ty Probe
senses the distance between the tip of the Proximity
Probe and the surface of the High Speed Thrust collar.
An ear li er vintage Probe (025-30961-000) also sensed
the High Speed Drain Line oil temperature. How ev er,
regardless of which Probe is installed, chill ers equipped
with Flash Memory Card version C.MLM.01.03 or
lat er do not sense the High Speed Drain Line oil tem-
per a ture.
The output of the Proximity circuit is connected to the
Microboard at J8-15 and is a 0 (0.089VDC) to +4.4VDC
analog voltage corresponding to a mea sured distance of
10 to 99 mils. This is the PROX IM I TY POSITION and
is displayed as "High Speed Thrust Bearing Prox im i ty
Position = xx mils" on the Prox im i ty Probe Cal i bra tion
Screen. The output of the 025-30961-000 Probe Temper-
ature circuit is con nect ed to the Microboard at J8-1 and is
a 0 to +4.5VDC analog volt age cor re spond ing to a mea-
sured temperature of 0
(-177
ºF
This is the OIL DRAIN LINE TEM PER A TURE and
is displayed as "High Speed Thrust Bearing Oil Drain
Tem per a ture = xxx
F on the Com pres sor Screen (not
º
ap pli ca ble to Flash Memory Card version C.MLM.01.03
or later).
When the Probe is installed at the time of chiller man-
u fac ture, a reference position is established. It is the
dis tance between the tip of the Probe and the surface
of the High Speed Thrust Collar with a minimum of
25 PSID oil pressure. Any distance between 37 and 79
mils is acceptable. It is established using a calibration
pro ce dure in the "System Cal i bra tion" section of this
book. This value is entered at the Keypad as the REF-
ER ENCE POSITION Setpoint using the Proximity
Probe Calibration Screen. Dis tanc es outside the range
of 37 to 79 mils will be rejected. The value is logged
on a label adhered to the inside of the
Cen ter door. This value remains the Reference Position
until the compressor is rebuilt, whereupon the calibration
procedure must be re peat ed to establish a new Ref er ence
Position. Since this Reference Position value is stored
in the BRAM (U52) memory device on the Microboard,
fi eld replacement of either of these items requires the
Reference Position Setpoint to be pro grammed again.
84
SECTION 13
PROXIMITY PROBE
(REFER TO FIG. 45 - 48)
C) to 300
(148.9
C).
º
ºF
º
Control
OptiView
The difference between the Reference Position and the
actual Position is the PROXIMITY DIF FER EN TIAL
and is displayed as "High Speed Thrust Bearing Prox-
im i ty Differential = xx mils" on the Compressor Screen.
For example, if the Reference Position is 50 mils and
the actual Position is 45 mils, then the Dif fer en tial is -5
mils; with the same Ref er ence, if the actual Position is
55 mils, the Differential is +5 mils.
If the Differential increases to > 10 mils (+10, +11, etc.) or
decreases to > 25 mils (-25, -26, etc.), a Safety shut down
is performed and "THRUST BEAR ING - PROX IM I TY
PROBE CLEARANCE" is displayed. The +10 thresh-
old only has to be exceeded for an instant to initiate a
shut down; the -25 threshold must be ex ceed ed for 2
con tin u ous seconds to initiate a shut down.
If the Reference Position is between 37 and 46 mils, the
full -25 mil differential is not allowed; the max i mum
al lowed distance between the tip of the Probe and the
surface of the Thrust Collar is 23 mils. Therefore, when
the distance decreases to < 22 mils, the Safety shut down
is performed, regardless of the Differential to the Refer-
ence Position.
If the distance decreases to < -17 mils, a safety shut down
is performed and "THRUST BEARING - PROX IM I TY
PROBE OUT OF RANGE" is dis played.
On chillers equipped with Probe 025-30961-000
and Flash Memory Card version C.MLM.01.02 and
ear li er, if the Drain Line Temperature increases to
>250.0
F (121.1
C), a Safety shutdown is per formed
º
º
and "THRUST BEARING - HIGH OIL TEM PER A-
TURE" is displayed. If the Temperature signal output
of the Probe decreases to 0VDC, it is indicative of an
open circuit or a broken wire to the Probe and a Safety
shut down is initiated and "THRUST BEAR ING - OIL
TEM PER A TURE SENSOR" is displayed.
When any of the above Thrust Bearing related Safety
shutdowns occur, the chiller cannot be restarted until a
special reset procedure is performed by a Service tech-
ni cian. Some of these shutdowns also require a thrust
bearing inspection. The reset procedure and bearing
inspection criteria is listed in the "System Calibration,
Service Setpoints and Reset Procedures" section of this
book.
FORM 160.54-M1(503)
YORK INTERNATIONAL
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