On the display
The panel shows WARNING - MBC - ROTATION MODE OFF. Both manuals print the message in exactly this wording, and it is the only variant given; it is listed with the YORK YMC2's warning messages.
What it means
The microboard commands the MBC Rotation Mode ON via serial comms, and the MBC reports its Rotation Mode status back over the same serial comms. The warning is set while the MBC reports Rotation Mode OFF at a time when the microboard is commanding Rotation Mode ON — a mismatch between the command sent to the MBC and the status the MBC returns.
Why it appears
- The MBC reports Rotation Mode OFF by serial comms during the time the MBC Rotation Mode is commanded ON by the microboard via serial comms. This reported mismatch is the only condition the manuals give for setting the warning; no separate hardware or wiring cause is listed.
What to check
- Confirm that the warning is occurring while the microboard is commanding MBC Rotation Mode ON via serial comms — the manual sets the warning only during that command.
- Check whether MBC communication is initiated — the warning is inhibited if MBC communication is not initiated.
- Check whether the warning appeared within the first 15 seconds after Rotation Mode was commanded ON — the warning is inhibited during that window, so an active warning appeared after it.
- Read the Rotation Mode status the MBC reports by serial comms and compare it with the microboard's ON command — the warning remains set until the two match.
Setpoints and thresholds
- 15 seconds — the warning is inhibited during the first 15 seconds after the Rotation Mode is commanded ON.
- MBC communication — the warning is also inhibited if MBC communication is not initiated.
- Release condition — the warning is released when Rotation Mode status matches the microboard command to the MBC.
Reset and restart
The manuals describe no manual reset for this warning; it clears on its own when the reported status comes back in line with the command. This warning is released when Rotation Mode status matches the microboard command to the MBC.
Until the Rotation Mode status the MBC reports over serial comms again matches the microboard's ON command, the warning remains set.
Questions engineers ask
What does WARNING - MBC - ROTATION MODE OFF mean on a YORK YMC2?
It means the MBC is reporting Rotation Mode OFF by serial comms while the microboard is commanding MBC Rotation Mode ON via serial comms. The warning flags that mismatch between the microboard's command and the status the MBC returns.
How do I clear the WARNING - MBC - ROTATION MODE OFF warning?
The manuals describe no manual reset. The warning is released automatically when the Rotation Mode status reported by the MBC matches the microboard command to the MBC.
Why does the warning not appear immediately after Rotation Mode is commanded ON?
The warning is inhibited during the first 15 seconds after Rotation Mode is commanded ON, and it is also inhibited if MBC communication is not initiated. A warning that shows on the display therefore set after that window.
Messages next to this one
Source
Written from the manufacturer's manuals for the YORK YMC2; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YMC2 messages: fault codes · YORK YMC2 documentation · YORK manuals