On the display
The panel shows the shutdown as LCSSS - Low supply line voltage; on some control centers it is printed in capitals as LCSSS - LOW SUPPLY LINE VOLTAGE. The message belongs to the liquid cooled solid state starter group of display messages and is a cycling shutdown: the chiller stops, and the message stays on the display until the voltage recovers and the restart conditions are met.
What it means
The LCSSS logic/trigger board has detected that the compressor motor AC power line voltage, in any phase, decreased below the low line voltage threshold and stayed there continuously for 20 seconds. The starter watches the phase-to-phase RMS input voltage against the low supply limit programmed for the selected voltage range; on a 440 to 480 V supply, for example, the shutdown level while running is 370 V and the restart level is 400 V. Two built-in exceptions apply: the detection is disabled for the first 20 seconds of the starter run, and it is disabled completely if no voltage range is programmed.
Why it appears
- An improper voltage range selected at the control center.
- Improper line voltage applied to the starter.
- During generator operation, the generator responding slowly to load changes.
What to check
- Verify that the proper voltage range is selected at the control center.
- Verify that proper line voltage is being applied to the starter.
- If the problem occurs during generator operation, add some standby load to the generator so that it can respond more quickly to load changes.
Setpoints and thresholds
- No voltage range programmed: detection disabled.
- 200 to 208 V supply: shutdown 160 V, restart 174 V.
- 220 to 240 V supply: shutdown 185 V, restart 200 V.
- 380 V supply: shutdown 305 V, restart 331 V.
- 400 V supply: shutdown 320 V, restart 349 V.
- 415 V supply: shutdown 335 V, restart 362 V.
- 440 to 480 V supply: shutdown 370 V, restart 400 V.
- 550 to 600 V supply: shutdown 460 V, restart 502 V.
- Detection is disabled for the first 20 seconds of the starter run.
Reset and restart
No manual reset is described for this message. The chiller automatically restarts when the voltage in all phases returns to the restart level.
The restart happens after coastdown, provided the shutdown is no longer active and the compressor switch is still in the run position. If the shutdown keeps occurring during generator operation, adding some standby load to the generator lets it respond more quickly to load changes.
Questions engineers ask
What does LCSSS - Low supply line voltage mean on a YORK YK chiller?
The solid-state starter's LCSSS logic/trigger board has seen the compressor motor AC power line voltage, in any phase, below the low line voltage threshold continuously for 20 seconds, so the chiller shuts down.
Why does my YORK YK show LCSSS - LOW SUPPLY LINE VOLTAGE?
The manual lists three possible problems: an improper voltage range selected at the control center, improper line voltage applied to the starter, or — during generator operation — a generator that responds slowly to load changes.
At what voltage does a YORK YK trip on low supply line voltage?
It depends on the programmed voltage range; for 440 to 480 V the shutdown level is 370 V while running and the restart level is 400 V, and the page lists every range from 200 to 208 V up to 550 to 600 V.
Does the chiller restart by itself after this shutdown?
Yes. It restarts automatically after coastdown once the voltage in all phases is back above the restart level, as long as the shutdown is no longer active and the compressor switch is still in the run position.
Messages next to this one
Source
Written from the manufacturer's manuals for the YORK YK; every number and designation on this page is checked against them before publication. The row of the manual this message comes from:
All YORK YK messages: fault codes · YORK YK documentation · YORK manuals