YORK YMC2 — WARNING - MBC - HIGH RADIAL OSCILLATOR VOLTAGE

The panel shows WARNING - MBC - HIGH RADIAL OSCILLATOR VOLTAGE. The manual prints this exact wording as the only variant. It appears in two listings of the same manual — as a manual reset warning and among the safety shutdown messages — with the same description in both places.

The internal oscillator that drives the radial position sensor coil has been overloaded for one continuous second. This oscillator feeds the coil of the sensor that reports the radial position of the shaft, so the message concerns that sensing circuit. While the condition is set, the MBC Fault contacts open. The manual treats the message as a manual reset warning: releasing it requires both a normal oscillator voltage and a reset action by the operator.

• An opening in the connection to the shaft position sensor — the cause the manual names as typical.
• A failure of the MBC control board.

• The overload must last one continuous second for the message to be set; the manual prints no adjustable setpoint for this warning.

The oscillator voltage has to return to normal before anything else. The manual then gives the reset path: this message will clear when the voltage is normal and the warning reset key is pressed in operator (or higher) access mode. In the safety shutdown description, the condition is released when the oscillator voltage drop is normal, and the chiller can be started when the condition is released and the OptiView panel clear faults button is pressed.