YORK YMC2 — SURGE PROTECTION - EXCESS SURGE

The panel shows SURGE PROTECTION - EXCESS SURGE. Both YMC2 manuals print the message in this single form, so there are no wording variants to watch for. It belongs to the safety shutdown messages: it is displayed when the control center performs a safety shutdown, and it appears only while the Surge Protection shutdown feature is enabled.

The message means that the Surge Window Count — the number of surge events recorded during the Count Window period — has exceeded the Count Limit setpoint. This applies only if the Surge Protection SHUTDOWN feature is Enabled. When an excess surge situation is detected and the Shutdown setpoint is enabled, the chiller performs a safety shutdown and displays this message; the chiller shuts down as soon as the count exceeds the limit.

• The Surge Window Count of surge events exceeded the Count Limit setpoint within the Count Window period; this detection applies only if the Surge Protection SHUTDOWN feature is Enabled.
• The manuals give no other cause for this message.

1. Confirm at the control center that the Surge Protection SHUTDOWN feature is Enabled — the message applies only when it is.
2. Review the Count Window setpoint (OPERATOR access): the period of time, selectable from 1 to 5 minutes, in which the number of surge events is compared to the maximum allowed, for the purpose of detecting an excess surge situation.
3. Review the Count Limit setpoint (OPERATOR access): the maximum number of surge events, selectable from 4 to 20, that can occur within the defined period before an excess surge situation is detected.
4. Check the Surge Sensitivity setting (SERVICE access): selectable from 0.3 to 1.3 with a default of 0.3; the smaller the number, the greater the surge detection sensitivity.

• Count Window (access level OPERATOR): defines the period of time in which the surge window count is compared to the maximum allowed (count limit). Range 1 to 5 minutes; the manual lists two defaults for this setpoint, 5 and 3 minutes.
• Count Limit (access level OPERATOR): the maximum number of surge events that can occur within the defined period before an excess surge situation is detected. Range 4 to 20; the manual lists two defaults for this setpoint, 4 and 15.
• Surge Sensitivity (access level SERVICE): sets the surge detection sensitivity of the Surge Protection feature. Range 0.3 to 1.3, default 0.3; the smaller the number, the greater the sensitivity.
• Shutdown setpoint: when enabled, a safety shutdown is performed when the surge window count exceeds the count limit, and SURGE PROTECTION - EXCESS SURGE is displayed.
• Clear Surge Count (access level ADMIN): allows the user to set the Total Surge Count to zero.

This is a safety shutdown: the chiller shuts down as soon as the surge window count exceeds the count limit. Recovery is the single step the manuals give for this message: The chiller can be started after the CLEAR FAULT button is pressed. The manuals describe no further reset actions for this message.