Carrier 17/19EX - Manual (Page 49)

Water flow through the oil cooler is manually adjusted by a plug valve (Item 9) to maintain the
oil at an operating temperature of approximately 145 F (63 C). During shutdown, the oil
temperature is also maintained at 150 to 160 F (65 to 71 C) by an immersion heater (Item 3) in
order to minimize absorption of refrigerant by the oil.
Upon leaving the oil cooler, the oil is filtered (11) and a portion is directed to the seal-end
bearing (17) and the shaft seal (18). The remainder lubricates the compressor transmission (15)
and the thrust and journal bearings (10). Thrust bearing temperature is indicated by the PIC
controls. Oil from both circuits returns by gravity to the reservoir.
A demister (13 and 16), by centrifugal action, draws refrigerant gas from the transmission
area to a housing that is vented to the cooler (Item 19). The resulting pressure difference
prevents oil from the transmission cavity from leaking into the seal.
The open compressor drive requires that the shaft seal (18) be kept full of lubrication oil,
even when the machine is not operating, to prevent loss of refrigerant.
If the machine is not operating and the oil pump has not operated during the last 12 hours,
the control system will automatically run the oil pump for one minute in order to keep the contact
seal filled with oil.
IMPORTANT: If the control power is to be deenergized for more than one day, the
machine refrigerant should be pumped over to the utility vessel.