YORK YCAV — UNIT LOW LEAVING CHILLED LIQUID TEMP

The display reads UNIT LOW LEAVING CHILLED LIQUID TEMP. In the manuals' fault tables the line is printed as UNIT YYYYYYYY LOW LEAVING CHILLED LIQUID TEMP, with a placeholder printed after the word UNIT; this is the only form the manuals give for the message. It is listed among the unit safeties.

This is a unit safety that helps protect the chiller from an evaporator freeze-up. It trips when the leaving chilled liquid temperature — water or brine — drops below the programmable cutout point. The unit responds with a controlled ramped shutdown, and the fault cannot cause a lockout.

• Low flow conditions.
• Improperly programmed micro panel setpoint values.

1. Check the chilled liquid circuit for low flow conditions, which the manuals name as a situation that can pull the leaving chilled liquid temperature below the cutout point.
2. Verify that the micro panel setpoint values are properly programmed, since improperly programmed values are the other cause the manuals give.
3. Confirm that the leaving chilled liquid temperature has risen above the cutout + 4°F before expecting a start; the unit is inhibited from starting any time the chilled liquid temperature is below that level.

• Leaving chilled liquid temperature cutout point — programmable; no numerical value for it is printed on this page.
• Restart point — chilled liquid temperature 4°F above the cutout, and only if demand allows.
• Start inhibit threshold — cutout + 4°F; below it the unit will not start.

No manual reset is described, and none is needed: the fault cannot cause a lockout, so there is nothing to clear by hand. After the controlled ramped shutdown the unit comes back on its own once conditions allow. Restart can occur, if demand allows, when chilled liquid temperature rises 4°F above the cutout. Until the temperature reaches that level, the unit remains inhibited from starting.