Carrier 19XL - Manual (Page 206)

Check Safety and Operating Controls Monthly
To ensure machine protection, the Control Test Automated Test should be done at least
once per month. See Table 3 for safety control settings. See Table 8 for Control Test functions.
Changing Oil Filter
Change the oil filter on a yearly basis or when the machine is opened for repairs. The 19XL
has an isolatable oil filter so that the filter may be changed with the refrigerant remaining in the
machine. Use the following procedure:
1. Make sure that the compressor is off, and the disconnect for the compressor is open.
2. Disconnect the power to the oil pump.
3. Close the oil filter isolation valves ( Figure 4 ).
4. Connect an oil charging hose from the oil charging valve ( Figure 4 ), and place the other end
in a clean container suitable for used oil. The oil drained from the filter housing should be
used as an oil sample to be sent to a laboratory for proper analysis. Do not contaminate this
sample .
5. Slowly open the charging valve to drain the oil from the housing.