Carrier 19XL - Manual (Page 209)

4. When the machine pressure is 5 psi (34 kPa) or less, drain the oil reservoir by opening the
oil charging valve ( Figure 2A or Figure 2B ). Slowly open the valve against refrigerant
pressure.
5. Change the oil filter at this time. See Changing Oil Filter section.
6. Change the refrigerant filter at this time, see the next section, Refrigerant Filter .
7. Charge the machine with oil. Charge until the oil level is equal to the oil level marked in Step
2. Turn on the power to the oil heater and let the PIC warm it up to at least 140 F (60 C).
Operate the oil pump manually, through the Control Test, for 2 minutes. The oil level should
be full in the lower sight glass for shutdown conditions. If the oil level is above 1/2 full in the
upper sight glass, remove the excess oil. The oil level should now be equal to the amount
shown in Step 2.
Refrigerant Filter
A refrigerant filter/drier, located on the refrigerant cooling line to the motor ( Figure 2A or
Figure 2B ), should be changed once a year, or more often if filter condition indicates a need for
more frequent replacement. Change the filter with the machine pressure at 0 psig (0 kPa) by
transferring the refrigerant to the condenser vessel, (if isolation valves are present), or a storage
tank. A moisture indicator sight glass is located beyond this filter to indicate the volume and
moisture in the refrigerant. If the moisture indicator (dry-eye) indicates moisture, locate the
source of water immediately by performing a thorough leak check.