PSIO Software Version 09 and Higher

The oil heater relay is energized whenever the chiller compressor is off and the oil sump temperature is less than 150 F (65.6 C) or the oil sump temperature is less than the cooler refrigerant temperature plus 70° F (39° C). The oil heater is turned off when the oil sump temperature is either 1) more than 160 F (71.1 C); or 2) the oil sump temperature is more than 155 F (68.3 C) and more than the cooler refrigerant temperature plus 75° F (41.6° C). The oil heater is always off during start-up or when the compressor is running.

When a power failure to the PSIO module has occurred for more than 3 hours (i.e., initial

start-up), the oil sump is heated to 100° F (56° C) above the evaporator refrigerant temperature or 190 F (88 C), whichever is lower. Once this temperature is reached, the oil pump will be energized for 1 to 2 minutes or until the oil sump temperature cools to below 145 F (63 C). The normal heating algorithm is now followed once ramp loading has been completed.

After a 3-hour power failure, the oil temperature must rise to the higher oil temperature. The controls will delay the start of the compressor until this temperature is met.

Oil Cooler

The oil must be cooled when the compressor is running. This is accomplished through a small, plate-type heat exchanger located behind the oil pump. The heat exchanger uses liquid condenser refrigerant as the cooling liquid. A refrigerant thermal expansion valve (TXV) regulates refrigerant flow to control oil temperature entering the bearings. There is always a flow

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Carrier PC211 specifications Oil Cooler, Psio Software Version 09 and Higher