Carrier 19XL - Manual (Page 90)

Auto. Restart After Power Failure
This option may be enabled or disabled, and may be viewed/modified in the Config table of
Equipment Configuration. If enabled, the chiller will start up automatically after a single cycle
dropout, low, high, or loss of voltage has occurred, and the power is within ±10% of normal. The
15- and 3-minute inhibit timers are ignored during this type of start-up.
When power is restored after the power failure, and if the compressor had been running, the
oil pump will be energized for one minute prior to the evaporator pump energizing. Auto restart
will then continue like a normal start-up.
If power to the PSIO module has been off for more than 3 hours, the PIC will raise the oil
temperature 100° F (56° C) above the evaporator temperature. Refrigerant normally migrates
into the oil when the oil heater is left off for extended periods of time. The PIC operates the oil
pump for 1 to 2 minutes to ensure that the oil is free of excess refrigerant. Once this algorithm is
completed, the RESTART of the chiller will continue.
Water/Brine Reset
Three types of chilled water or brine reset are available and can be viewed or modified on the
Equipment Configuration table Config selection.
The LID default screen status message indicates when the chilled water reset is active. The
Control Point temperature on the Status01 table indicates the machine’s current reset
temperature.