Carrier PC211 specifications High Discharge Temperature Control, Oil Sump Temperature Control

High Discharge Temperature Control

If the discharge temperature increases above 160 F (71.1 C) (PSIO Software Version 09 and higher) or 180 F (82 C) (PSIO Software Version 08 or lower), the guide vanes are proportionally opened to increase gas flow through the compressor. If the leaving chilled water temperature is then brought 5° F (2.8° C) below the control set point temperature, the controls will bring the machine into the recycle mode.

Oil Sump Temperature Control

The oil sump temperature control is regulated by the PIC which uses the oil heater relay when the machine is shut down.

As part of the pre-start checks executed by the controls, oil sump temperature is compared against evaporator refrigerant temperature. If the difference between these 2 temperatures is 50 F (27.8 C) or less, the start-up will be delayed until the oil temperature is 50 F (27.8 C) or more. Once this temperature is confirmed, the start-up continues.

PSIO Software Version 08 and Lower

The oil heater relay is energized whenever the chiller compressor is off, and the oil sump temperature is less than 140 F (60 C) or sump temperature is less than the cooler refrigerant temperature plus 60° F (33.3° C). The heater is then turned off when the oil sump temperature is: 1) more than 160 F (71.1 C); or 2) the sump temperature is more than 145 F (62.8 C) and more than the cooler refrigerant temperature plus 65° F (36.1° C). The heater is always off during start-up or when the compressor is running.