On the display
The display reads SYS X SENSOR FAILURE, printed in the manuals as SYS X YYYYYYYY SENSOR FAILURE: ZZZZZZZZZZZZ. X is the system number. YYYYYYYY reads FAULT or LOCKOUT. ZZZZZZZZZZZZ names the failed sensor: SUCT PRESS, OIL PRESS, DSCH PRESS, ECONOMIZER PRESS or MOTOR TEMP X, a specific motor temperature sensor.
What it means
This is the Sensor Failure Cutout. The system will not run when a critical sensor — a transducer, level sensor or motor winding temperature sensor — is not functioning properly and reading out of range. The safety is checked at startup, where it prevents the system from running, and also during operation: if a safety threshold is exceeded or a sensor reads out of range high or low, the system faults and shuts down.
Why it appears
- The sensor named by ZZZZZZZZZZZZ has failed or is reading out of range (high or low): SUCT PRESS, OIL PRESS, DSCH PRESS, ECONOMIZER PRESS or MOTOR TEMP X.
- While the system is running, a safety threshold is exceeded or a sensor reads out of range, which faults and shuts the system down.
- A critical sensor — transducer, level sensor or motor winding temperature sensor — is not functioning properly.
What to check
- Read ZZZZZZZZZZZZ on the display to identify the failed sensor: SUCT PRESS, OIL PRESS, DSCH PRESS, ECONOMIZER PRESS or MOTOR TEMP X.
- For a failed suction, oil or discharge transducer, check the transducer signal against the start inhibit threshold of 0.3 to 4.7 VDC.
- For MOTOR TEMP X, check the sensor reading against 0°C (0°F) to 116°C (240°F).
- If a specific motor temperature sensor has failed, it can be ignored using the Unit Setup Mode.
- Report any failure to Johnson Controls service for investigation.
Setpoints and thresholds
- Start inhibit sensor thresholds: Suction Transducer 0.3 to 4.7 VDC; Oil Transducer 0.3 to 4.7 VDC; Discharge Transducer 0.3 to 4.7 VDC.
- Motor Temp. Sensor: 0°C (0°F) to 116°C (240°F).
Reset and restart
If YYYYYYYY reads FAULT, the system restarts when the fault clears; the reset is automatic after the 120 s anti-recycle timer. After 3 faults the message shows LOCKOUT and the system will not restart until the operator clears the fault using the keypad, or as the manual puts it, cycle the respective system switch OFF and ON to clear
. A specific motor temperature sensor can be ignored in the Unit Setup Mode if it fails; report any failure to Johnson Controls service for investigation.
Questions engineers ask
What does SYS X SENSOR FAILURE mean on a YORK YVAA?
It is the Sensor Failure Cutout: a critical sensor — a transducer, level sensor or motor winding temperature sensor — is not functioning properly and reading out of range, so the system is prevented from running at startup or faults and shuts down during operation.
Which sensor has failed when this message appears?
The ZZZZZZZZZZZZ part of the display names it: SUCT PRESS, OIL PRESS, DSCH PRESS, ECONOMIZER PRESS or MOTOR TEMP X, a specific motor temperature sensor. X after SYS is the system number.
How do I clear a LOCKOUT after SYS X SENSOR FAILURE?
After 3 faults the message reads LOCKOUT and the system will not restart until the operator clears the fault using the keypad, or cycles the respective system switch OFF and ON. A plain FAULT resets itself once the fault clears, after the 120 s anti-recycle timer.
What sensor readings trigger SYS X SENSOR FAILURE?
The start inhibit thresholds are 0.3 to 4.7 VDC for the suction, oil and discharge transducers, and 0°C (0°F) to 116°C (240°F) for the motor temperature sensor.
Messages next to this one
The same message on other models
Source
Written from the manufacturer's manuals for the YORK YVAA; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YVAA messages: fault codes · YORK YVAA documentation · YORK manuals