Operating instructions

IMM AGSB-60 57
System Maintenance
General
On initial start-up and periodically during operation, it will be necessary to perform certain
routine service checks. Among these are checking the liquid line sight glasses, evaporator
sight glasses, and oil separator sight glasses, plus taking a full set of refrigerant pressure and
temperature readings. Through the MicroTech II keypad, check to see that the unit has normal
superheat and subcooling readings. A recommended maintenance schedule is located at the
end of this section.
A Periodic Maintenance Log is located at the end of this manual. It is suggested that the log be
copied and a report be completed on a regular basis. The log will serve as a useful tool for a
service technician in the event service is required.
Initial start-up data including evaporator pressure drop, vibration readings, compressor megger
readings and oil analysis information should be kept for reference base-line data.
Compressor Maintenance
Since the compressor is semi-hermetic, no yearly compressor maintenance is normally
required, however, vibration is an excellent check for proper mechanical operation.
Compressor vibration is an indicator of the requirement for maintenance and contributes to a
decrease in unit performance and efficiency. It is recommended that the compressor be
checked with a vibration analyzer at, or shortly after, start-up and again on an annual basis.
The load should be maintained as closely as possible to the load of the original test. The initial
vibration analyzer test provides a benchmark of the compressor, and when performed routinely,
can give a warning of impending problems.
Lubrication
No routine lubrication is required on AGS units. The fan motor bearings are permanently
lubricated. No further lubrication is required. Excessive fan motor bearing noise is an
indication of a potential bearing failure.
Compressor oil must be ICI RL68HP, McQuay Part Number 735030442 in a 1-gallon
container, or ICI RL68H, Part Number 735030444 in a 1-gallon size. This is synthetic
polyolester oil with anti-wear additives and is highly hygroscopic. Care must be taken to
minimize exposure of the oil to air when charging oil into the system.
On early units, an oil filter is located in the oil return line from the oil separator to the
compressor.
Figure 31, Compressor Oil Filter
On later units, the oil filter resides in the compressor
housing as shown in Figure 31. Units without a suction
service shutoff valve require pumping down the circuit
in order to change the filter.
This filter should be replaced after one month of
operation or if the pressure drop exceeds 7 psi (48 kPa)
as measured at Schrader fittings up and down stream
from the filter.
Oil Filter Housin
g