The York 025-40496-000 is a two-piece proximity probe for YK centrifugal chillers. It measures the distance between the compressor's high-speed thrust collar and the probe tip, which the OptiView panel uses for its thrust bearing safeties (York form 160.54-O1). York service information SI0142 says the two-piece design lets you replace the electronics module without evacuating the refrigerant charge, and that it is not compatible with compressors that use a proximity switch.
What does the proximity probe do?
York form 160.54-O1, the OptiView operation manual for YK chillers through Style G, shows a value called High Speed Thrust Bearing Proximity Differential on the compressor screen. The manual says it displays the distance between the high-speed thrust collar and the tip of the proximity probe, and that it takes into account a reference position set when the compressor was manufactured. The same screen leads to a service-level subscreen for calibrating the probe.
In other words, the probe watches the high-speed shaft's thrust position. If the collar moves too far from where it started, the panel stops the chiller.
Which shutdowns involve the proximity probe?
Form 160.54-O1 lists two thrust bearing safety shutdowns based on the probe. Both apply to Style E and earlier chillers with G, H or J compressors, and to Style F and later chillers with J or H3 compressors.
| Message | What 160.54-O1 says triggers it |
|---|---|
| Thrust Bearing – Proximity Probe Clearance | The collar-to-probe clearance has increased more than +10 mils or decreased to less than –25 mils from the reference position, for 2 continuous seconds |
| Thrust Bearing – Proximity Probe Out Of Range | The collar-to-probe clearance has decreased to less than 17 mils |
With software C.MLM.01.10.xxx and later, or C.OPT.01.10.302 and later, the manual says clearance is checked only during the last 20 seconds of system prelube, during system run and during coastdown. On earlier software, the +10 mil threshold acted instantly rather than after 2 seconds.
For both messages, the manual says the shutdown must be evaluated by a qualified service technician before the chiller is started, and that starting without that evaluation could result in severe compressor damage. Restart is inhibited until the clearance is within acceptable limits (for the out-of-range message, within +10 to –25 mils of the reference position) and the technician performs a special reset procedure. That procedure is in the OptiView service instructions, form 160.54-M1.
On older flash memory card software, 160.54-O1 also lists two messages where the probe senses oil temperature in the high-speed thrust bearing drain line: "Thrust Bearing – High Oil Temperature" at 250.0°F or higher, and "Thrust Bearing – Oil Temperature Sensor" below 50.0°F. The manual marks both as not applicable to flash memory card version C.MLM.01.03 and later.
When should the probe be replaced?
York's documents do not say "replace the probe" when a clearance or out-of-range shutdown appears. They say to have the shutdown evaluated by a service technician first. A clearance shutdown may be reporting real movement of the thrust collar, and a new probe would not fix that. Our practical advice is to treat probe replacement as the result of that evaluation, not the first step.
SI0142 gives one replacement instruction directly: replace the cable between the electronics module and the control panel if an intermittent connection is suspected. The two-piece design matters here too. Because the probe tip and the electronics module are separate parts, SI0142 says the module can be replaced without evacuating the chiller's refrigerant charge.
What is in 025-40496-000 and the retrofit kit?
SI0142 (revision 2-09, which supersedes SI0142 (606)) says the new probe's part number 025-40496-000 includes the probe tip, the electronics module, a PVC bushing and the cable from the probe tip to the module. For a retrofit from a single-piece probe, SI0142 says all items shown in its figure are needed. It lists kit 364-51806-000 as including 025-40496-000, the DIN connector, the probe tip O-ring and the instruction drawing; the cable to the control panel is marked 'Replace If Defective'.
| SI0142 item | Part number |
|---|---|
| Probe package (tip, module, bushing, cable) | 025-40496-000 |
| Proximity probe tip | 025-40496-001 |
| Electronics module with PVC bushing | 025-40496-002 |
| Connecting cable, probe to module | 025-40496-003 |
| DIN connector | 025-37805-000 |
| Probe tip O-ring | 028-12209-000 |
| Instruction drawing | 035-21458-000 |
| Connecting cable to control panel (replace if defective) | 025-28701-003 |
| Retrofit kit (025-40496-000, DIN connector, O-ring, drawing) | 364-51806-000 |
SI0142 says the electronics module now mounts in the "D" flange or motor adapter, or on a bracket on units without one.
Installation points from SI0142
| Item | Torque | Tool |
|---|---|---|
| Probe to compressor | 20 in-lb | 7/8" wrench |
| Electronics module | 20 in-lb | 2" wrench |
| Interconnecting cable ends | 2 in-lb | No tools |
- Cable install. Plug the cable connector into the mating connector on each component and turn only the connector's hex nut. Do not hold the cable and rotate the probe or module.
- Signal and power. On an OptiView panel, pin 2 at the DIN connector sends the signal to J8-15 on the microboard. The wiring diagram shows a +24 VDC power source, and notes that pin 3 is not used.
- Thermocouple probes. If you are replacing a probe that uses a thermocouple to detect high-speed drain temperature, the software version must be xxx.19 or higher.
Will it fit my YK?
SI0142 says the two-piece probe is backward compatible on all YK chillers and was being factory installed on new chillers when the SI was issued. It is not compatible with compressors using a proximity switch. If your compressor has a proximity switch rather than a probe, do not order this probe on that basis alone; send us the nameplate first.
Parts involved
| Component | Role in this issue | Where to find it |
|---|---|---|
| Two-piece proximity probe | The SI0142 probe package: tip, module, bushing and probe-to-module cable. | York 025-40496-000 Probe System, Proximity #ECP336 | OEM Chiller Part |
| Retrofit kit | SI0142 lists 364-51806-000 as the single-piece retrofit kit. Our listing's title reads 'Probe, Proximity' and its fit data names YD models, so ask us to confirm contents and fit before ordering. | York 364-51806-000 Probe, Proximity | OEM Chiller Part |
| DIN connector | The connector SI0142 lists for the retrofit. | York 025-37805-000 Connector, DIN 43650 | OEM Chiller Part |
| Module-to-panel cable | SI0142 says to replace it if an intermittent connection is suspected. | York 025-28701-003 Wire 3 CONDTR W/FOIL Shield | OEM Chiller Part |
| Other YK parts | We do not list the tip, module, probe cable or O-ring separately. Contact us for those numbers. | York YK Centrifugal Chiller Parts |
Scope: Probe contents, retrofit items, torques, wiring and compatibility come from York service information SI0142 (revision 2-09). The display value and shutdown messages come from York form 160.54-O1, the OptiView operation manual for YK chillers through Style G (issue date 11/19/2021); YK Style H and J panels have their own manual. The products above are examples listed by live title, not a fit confirmation for your chiller.
Before you order
Confirm the chiller's model, style and serial number and the compressor code from the nameplate, and note whether the compressor has a one-piece probe, a two-piece probe or a proximity switch. For other OptiView messages, see York Chiller Fault Codes: What OptiView Shutdown Messages Mean. To confirm fit, contact us at help@totalhvacparts.com or 302-219-4994 with the model, serial number and compressor code.
Frequently Asked Questions
What does the proximity probe do on a York YK chiller?
It measures the distance between the compressor's high-speed thrust collar and the probe tip. York form 160.54-O1 shows this as the High Speed Thrust Bearing Proximity Differential, relative to a reference position set at compressor manufacture.
Do you have to evacuate the refrigerant charge to replace a York proximity probe?
Not for the electronics module on the two-piece probe. York SI0142 says the two-piece design eliminates the need to evacuate the refrigerant charge when replacing the module. SI0142 does not make that statement about the probe tip.
What is the torque for a York 025-40496 proximity probe?
York SI0142 gives 20 in-lb for the probe to the compressor (7/8" wrench), 20 in-lb for the electronics module (2" wrench) and 2 in-lb for the interconnecting cable ends, with no tools.
What does York Thrust Bearing – Proximity Probe Clearance mean?
Per York form 160.54-O1, the thrust collar has moved more than +10 mils or –25 mils from its reference position for 2 seconds. A qualified technician must evaluate it and perform a special reset before restart.
Sources
- York service information SI0142, two-piece proximity probe now available (YK chillers) (probe contents, retrofit kit, torques, cable installation, wiring, compatibility)
- York form 160.54-O1, OptiView Control Center operation manual, YK through Style G (compressor screen; thrust bearing safety shutdown messages)
- Live product titles for the parts listed above, as shown on each product page
York centrifugal chillers involve line voltage, control circuits, refrigerant under pressure and high-speed rotating equipment. Service should be performed only by qualified personnel, following York's documentation for your chiller and your facility's lockout/tagout procedures.