YORK YCAV — High Flash Tank Level

The fault table prints the message as High Flash Tank Level. On the Status fault display it appears as SYS X YYYYYYYY HIGH FLASH TANK LEVEL, where X is the system number and YYYYYYYY stands for the indication that the system is in a FAULT condition. The manual introduces the safety as the High Flash Tank Level Cutout Fault; in the micropanel fault list it is entry 49, System Panel High Flash Tank Level.

The flash tank level cutout prevents the system from running when the liquid level in the flash tank is too high. The safety is ignored for the first 15 seconds of system operation; after that, a fault occurs if the tank level is greater than 85% for 10 seconds. When it trips, the shutdown is ramped — or soft ramped where soft shutdown is enabled — and the economizer solenoid is turned off during the ramp down. The manual notes that liquid floodback through the economizer line occurs due to a high flash tank level, which is why this level matters for compressor protection.

• An actual high liquid level in the flash tank — the condition the cutout exists to stop the system for.
• An intermittent level sensor. The manual states that high flash tank level faults are often caused by intermittent sensors that produce an output level spike which intermittently causes a fault.
• Level sensor output error. Typically there is an error of plus 15% or more in the level sensor output before a high flash tank fault occurs, so a displayed level can sit noticeably away from the true level.

1. Confirm the fault is real and repeats. The manufacturer's troubleshooting instruction for this message is written only for actual, repetitive system faults related to a high flash tank level, and it deliberately does not outline every possible cause — use it together with experience and good troubleshooting practice.
2. Before any work inside the panel, turn power OFF and check the DC bus with a meter to verify the voltage is less than 5VDC; the manual requires this check every time you work inside the panel. Work on the equipment is only for properly trained personnel, and protective clothing per Johnson Controls policy is required when checking live circuitry.
3. Watch the flash tank level indication on the panel while the system runs.
4. If an intermittent sensor is suspected, "lightly" tap the electronics enclosure of the level sensor with the handle of a screwdriver and watch the panel display for an erratic response.
5. If a significant error in the level sensor display is causing nuisance high flash tank level trips, the level sensor can normally be field re-calibrated; the manual gives the adjustment procedure for the new style sensors.
6. If a drain valve, feed valve or the level sensor must be changed, refrigerant does not need to be removed from the entire system — only from the low side. The manual describes running the compressor to pump the majority of the refrigerant into the high side of the condenser by closing the liquid line stop valve and opening the drain and feed valves to 100% in SERVICE mode.

• Trip condition: flash tank level greater than 85% for 10 seconds.
• Start-up grace: the safety is ignored for the first 15 seconds of system operation.
• Automatic restart: when the 120 second anti-recycle timer times out, unless the system is in LOCKOUT.
• Fault list entry: number 49, System Panel High Flash Tank Level.

What happens next depends on how the message sits on the display. A system shown in a FAULT condition restarts by itself when the 120 second anti-recycle timer times out. A system shown as LOCKOUT does not restart until the operator clears the fault using the keypad — the manual words it: will restart when the 120 second anti-recycle timer times out or "LOCK-OUT" and will not restart until the operator clears the fault using the keypad. No other reset procedure is given for this message.