YORK YMC2 — UPS - LINE LOW BATTERY VOLTAGE

The panel shows UPS - LINE LOW BATTERY VOLTAGE. This is the exact spelling the manual uses; there are no other variants. The manual places it in the group of cycling shutdown messages, so it is a fault that can stop the machine, not a passive notice.

This cycling fault concerns the UPS battery voltage. If it is set while the chiller state is Running, it initiates a soft shutdown. Behind it sits the matching Warning - UPS - Line Low Battery Voltage warning, which is set when line power is available and the Battery Voltage is below the Line Low Battery Voltage Threshold. The fault either follows that warning after it has persisted long enough, or is set directly from the same battery-voltage comparison while the unit is stopped.

• Chiller state Running or Soft Shutdown: the Battery Voltage Faults setting is enabled and the Warning - UPS - Line Low Battery Voltage warning has been set for 60 continuous minutes.
• Chiller state Stopped: the Battery Voltage Faults setting is enabled, the Control Voltage digital input is high (line power is available) and the Battery Voltage is below the Line Low Battery Voltage Threshold.

1. Check whether line power is available. While the chiller state is Stopped, the fault is only set when the Control Voltage digital input is high, which the manual gives as the indication that line power is present.
2. Check the state of the Battery Voltage Faults setting. It must be enabled for the fault to be set at all, and disabling it is also one of the release conditions.
3. Check the Battery Voltage against the Line Low Battery Voltage Threshold. While Stopped, the fault is set when Battery Voltage is below the threshold, and it releases once Battery Voltage rises more than 0.1 V above it.
4. Check how long the Warning - UPS - Line Low Battery Voltage warning has been set. If the chiller was Running or in Soft Shutdown, the fault appears only after that warning has stayed set for 60 continuous minutes.

• Battery Voltage Faults setting — enabling it arms the fault; the manual gives no default value for it.
• Line Low Battery Voltage Threshold — the Battery Voltage is compared against it; the manual gives no default value for it.
• 60 continuous minutes — how long the Warning - UPS - Line Low Battery Voltage warning must stay set before the fault is raised during Running or Soft Shutdown.
• 0.1 V — the margin by which the Battery Voltage must exceed the threshold for the fault to be released.

The manual describes no manual reset for this message; the control releases it on its own. Released when any of the following are true: Battery Voltage Faults is Disabled; Battery Voltage > Line Low Battery Voltage Threshold + 0.1 V. The Warning - UPS - Line Low Battery Voltage warning is described as an auto reset warning and releases under the same battery-voltage condition.