YORK YK — LCSSS - Phase locked loop

The panel shows LCSSS - Phase locked loop. The manual also prints the same shutdown in capitals, LCSSS - PHASE LOCKED LOOP. It belongs to the Liquid cooled solid state starter messages of this chiller.

The phase locked loop circuit on the LCSSS logic/trigger board was unable to maintain lock with phase A of the power line — the error signal of the synchronization circuit became too large and synchronization with the 'A' phase voltage was lost. If synchronization is not maintained, the SCRs will misfire and damage the chiller, which is why the shutdown is raised while the condition is present.

• Storms or other power problems make the frequency of the 'A' phase voltage change too rapidly; a power line anomaly can cause the sag or jitter that breaks the lock.
• During generator operation, the JP1 jumper has not been cut on a Rev. C or earlier Logic/Trigger Board.
• During generator operation, the generator responds slowly to load changes.

1. Note whether a storm or other power problem coincided with the shutdown; such anomalies can sag or jitter the power line and break the lock with phase A.
2. If the shutdown occurred during generator operation, ensure that the JP1 jumper has been cut (on Rev C. or earlier Logic/Trigger Boards).
3. If the problem occurs during generator operation, add some standby load to the generator so that it responds more quickly to load changes.

• The phase locked loop tolerates a power line frequency jitter of up to 3 Hz/s; faster changes in the line frequency can break the lock with phase A.

No manual reset is described for this shutdown. The chiller automatically restarts when lock has resumed. The manual adds that the restart is Automatic restart after coastdown if the shutdown is no longer active and the compressor switch is still in the run position.