YORK YMC2 — VSD - RUN SIGNAL

The panel reads VSD - RUN SIGNAL. Both manuals print the message with exactly this wording and give no other variant. It is listed in the table of cycling shutdown messages (Table 102), so it appears as a cycling shutdown of the chiller rather than a condition with a manual reset step.

The control center generates two redundant RUN commands for the VSD: one is sent hardwired on terminal TB6-24, the second travels over the Serial Communications link. When the VSD receives either of the two RUN commands, a 5 second timer commences. If both run commands are not received by the VSD Logic Board within those 5 seconds, the VSD performs a shutdown and this message is displayed. The cycling shutdown table describes the same shutdown as occurring when the run signal on TB6-24 is not received by the VSD Logic Board within the 5 seconds.

• The manuals state that this message is generally indicative of a wiring problem between the control center and the VSD.

1. Inspect the wiring between the control center and the VSD — both manuals name this as the general indication behind the message.
2. Check the run signal on TB6-24, the terminal on which the control center sends the hardwired one of the two redundant RUN commands and whose absence within the 5 second timer is described as triggering this shutdown.
3. Check the Serial Communications link between the control center and the VSD, the path that carries the second redundant RUN command.

• 5 seconds — the shutdown timer. It commences when the VSD receives either of the two RUN commands; the shutdown is performed if both run commands are not received by the VSD Logic Board within this time.

This is a cycling shutdown message and no manual reset is described for it. Recovery is automatic — The chiller will automatically restart when the cycling condition clears.