Carrier PC211 Capacity Override (Table 4)

Capacity Override (Table 4)
These can preven t some safety shutdowns caused by exceeding mo tor amperage limi t,
refrigerant low temp erature safety limit, mot or high temperature saf ety limit, and condenser hig h
pressure limit. In all cases there are 2 stages of compressor vane control.
1. The vanes are held from ope ning further, and the status line on the LID indicat es the reason
for the override.
2. The vanes are closed un ti l condition decreases bel ow the first step set point , and then the
vanes are released to normal capacity control.
Whenever the motor curr ent demand limit set point is r eac h ed, it activates a capac it y
override, again wit h a 2-step process. E xceeding 110% of the ra ted load amps for more than 30
seconds will initiat e a safety shutdown.
The compressor h igh lift (surg e prevention) se t point will caus e a capacity ov erride as well .
When the surge prevent ion set point is reached, the c ont roller normally will only hold the guide
vanes from opening. If s o equ ipped, the hot gas bypass v alv e will open instead of holdi ng the
vanes.
Click here f or Table 4 — Ca pacity Overrid es