SI0440 — YMC2 and YK Smart Sensor System (SSS) Installation Troubleshooting Instructions

Document type	Service Information Letter
Document number	SI0440
Equipment	YK Centrifugal Chiller
Brand	YORK
File size	0.4 MB

Fault codes in this document

PROBLEM: VSD Stop Contacts Open Fault Appears

Code / display	Meaning	Cause	Action	Page
VSD Stop Contacts Open	Fault appears on the OptiView panel display when 120 V AC is applied.	Possible causes identified by the troubleshooting procedure: fault indicated by the VSD logic board (fault LED lit near the J16 connector); wiring fault between J4 on the 031-03958 board and J14 on the 031-02911 board; 24 VDC power supply output outside 23–26 VDC or failed supply; missing 120 V AC feed to the power supply (HOT/NTRL miswired or open fuse); J1 not installed correctly or reversed polarity on the 031-03958 board; faulty cable between the boards; 031-02911 board in fault; failed 031-03958 board.	Check the fault LED near the J16 connector on the VSD logic board. If lit, the logic board is indicating a fault — refer to form 160.78-M3 (M1 motor), 160.84-M3 (M2 and M6 motor, YMC2 applications), or 160.00-M10 (YK applications, maximum 1100 HP [50 Hz] and 1300 HP [60 Hz] motors). If not lit, validate all wiring between J4 on the 031-03958 board and J14 on the 031-02911 board. Check the LED on the 24 VDC power supply: if lit, measure the output voltage (marked + and −) — if 23–26 VDC replace the 031-03958 board; if not, remove the J1 connector and re-measure (23–26 VDC → replace the 031-03958 board; not 23–26 VDC → replace the power supply). If the supply LED is not lit, measure 120 V AC between L and N: if present, replace the power supply; if absent, ensure the HOT and NTRL wires are properly connected (HOT to J2 pin 2 on the 031-03958 board and to the appropriate fuse, fuse not open; NTRL per the connection diagram). Check that J1 is installed correctly on the 031-03958 board; measure DC between J1 pin 1 (red lead) and pin 2 (black lead) — if 24 VDC is present but negative, ensure the brown (POS) wire is on the positive supply terminal and J1 pin 1 and the black (NEG) wire on the negative terminal and J1 pin 2; replace the 031-03958 board if unresolved. If 24 VDC is not present, remove J1 and measure the harness connector: 24 VDC → replace the 031-03958 board; no 24 VDC → correct the power-supply output wiring or replace the power supply. Measure AC voltage from J4 pin 2 to ground on the 031-03958 board: if not 120 V AC, measure J14 pin 4 on the 031-02911 board — if 120 V AC, correct or replace the cable (P/N 571-09367-205); if not 120 V AC, determine the reason the 031-02911 board is in fault. If J4 pin 2 reads 120 V AC, measure J4 pin 1 to ground: 120 V AC → the 031-03958 board is working properly; not 120 V AC → problem with the 24 VDC supply, the cable, or a failed 031-03958 board. If the problem is still not solved, contact PTS.	2

PROBLEM: Flip Dot Does Not Turn Black or Flips from Black to Red

Code / display	Meaning	Cause	Action	Page
Flip Dot Does Not Turn Black or Flips from Black to Red	When power is applied, the flip dot does not turn black or flips from black to red.	24 VDC not present between TB1 terminals R and L or at TB1 terminal L1 on the 031-03958 board; sensor bases wired incorrectly or sensors not installed correctly into the bases; L1 wire at TB1 installed incorrectly or wire insulation present in the terminal; failed 031-03958 board.	Measure DC voltage between TB1 terminal R and L on the 031-03958 board. If the voltage is 24 VDC, replace the 031-03958 board. If not 24 VDC, measure the DC voltage at TB1 terminal L1 on the 031-03958 board; ensure the base of the sensors is wired correctly and the sensors are installed correctly into the base. Remove the TB1 connector and re-measure at TB1 terminal L1: if 24 VDC, ensure the L1 wire connected to TB1 terminal L1 is installed correctly and no wire insulation is present in the terminal; if not 24 VDC, replace the 031-03958 board. If the problem is still not solved, contact PTS.	3

PROBLEM: Circuit Breaker Does Not Open

Code / display	Meaning	Cause	Action	Page
Circuit Breaker Does Not Open	The flip dot is red, but the circuit breaker does not open.	Shunt trip not latched correctly into the circuit breaker; incorrect connections between the SHNT wire and the YEL wire to the shunt trip, or the WHT wire from the shunt trip to the NTRL wire and back to the terminal block; long HOT wire not connected to the appropriate fuse or open fuse; failed 031-03958 board.	Measure AC voltage between J2 pin 2 on the 031-03958 board and ground. If 120 V AC, connect a jumper between J2 pin 2 and J2 pin 3 on the 031-03958 board (care: 120 V AC is present; do not apply the jumper for more than a few seconds — damage to the shunt trip may occur). If the shunt trip triggers but the circuit breaker does not open, ensure the shunt trip is installed according to the instructions — it may not be latched correctly into the circuit breaker. If the shunt trip does not trigger, check the connections between the SHNT wire and the YEL wire to the shunt trip, and the WHT wire from the shunt trip to the NTRL wire and back to the terminal block per the connection diagram; if the wiring is correct, replace the 031-03958 board. If the voltage is not 120 V AC, ensure the long HOT wire is connected to the appropriate fuse and the fuse is not open. If the problem is still not solved, contact PTS.	3

PROBLEM: When Conducting the Optical Sensor Test the Flip Dot Does Not Turn Red.

Code / display	Meaning	Cause	Action	Page
When Conducting the Optical Sensor Test the Flip Dot Does Not Turn Red.	The flip dot does not turn red during the optical sensor test.	Optical sensor test not conducted according to the instructions on the can of smoke; can of smoke not directed at the sensor with the black grill; wiring to the base of the sensors or at TB1 on the 031-03958 board installed incorrectly; sensor (white-grill or black-grill) whose LED does not light.	Determine if the optical sensor test is being conducted according to the instructions on the can of smoke; if not, repeat the test correctly. Make sure the can of smoke is directed at the sensor with the black grill. Remove the 120 V AC and remove both sensors; ensure the wiring to the base of both sensors and the wiring at TB1 on the 031-03958 board is correctly installed per the wiring diagram provided in the kit; correct any wiring error. Reinstall the sensor with the black grill, apply 120 V AC and repeat the test — the LED on the black-grill sensor should light. Then remove 120 V AC, reinstall the sensor with the white grill and reapply 120 V AC (this will reset the sensor); repeat the test — the LED on the black-grill sensor should light, and the system is working properly. If an LED is not lit, install a new sensor with the white grill, and if still not lit a new sensor with the black grill, repeating the optical sensor test after each replacement. If the problem is still not solved, contact PTS.	4

PROBLEM: When Conducting the CO Sensor Test the Flip Dot Does Not Turn Red.

Code / display	Meaning	Cause	Action	Page
When Conducting the CO Sensor Test the Flip Dot Does Not Turn Red.	The flip dot does not turn red during the CO sensor test.	CO sensor test not conducted per the installation instructions; can of CO not directed at the sensor with the white grill; wiring to the base of the sensors or at TB1 on the 031-03958 board installed incorrectly; sensor (black-grill or white-grill) whose LED does not light.	Determine if the CO sensor test is being conducted per the installation instructions; if not, repeat the test correctly. Make sure the can of CO is directed at the sensor with the white grill. Remove the 120 V AC and remove both sensors; ensure the wiring to the base of both sensors and the wiring at TB1 on the 031-03958 board is correctly installed per the wiring diagram provided in the kit; correct any wiring error. Reinstall the sensor with the white grill, apply 120 V AC and repeat the test — the LED on the white-grill sensor should light. Then remove 120 V AC, reinstall the sensor with the black grill and reapply 120 V AC (this will reset the sensor); repeat the test — the LED on the white-grill sensor should light, and the system is working properly. If an LED is not lit, install a new sensor with the black grill, and if still not lit a new sensor with the white grill, repeating the CO sensor test after each replacement. If the problem is still not solved, contact PTS.	5

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