98
IOMM ACZ/AGZ-1
Unit 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 sightglasses, taking condensing and
suction pressure readings, and checking to see that the unit has normal superheat and subcooling
readings. A recommended maintenance schedule is located at the end of this section.
Compressor Maintenance
The scroll compressors are fully hermetic and require no maintenance.
Lubrication
No routine lubrication is required on AGZ and ACZ units. The fan motor bearings are permanently
lubricated and no further lubrication is required. Excessive fan motor bearing noise is an indication of
a potential bearing failure.
Compressor oil should be standard refrigeration mineral oil such as Suniso 3GS.
Electrical Terminals
WARNING
Electric shock hazard. Turn off all power before continuing with following service.
Check terminals for tightness on a scheduled basis.
Condensers
The condensers are air-cooled and constructed of 3/8" (9.5mm) O.D. internally finned copper tubes
bonded in a staggered pattern into louvered aluminum fins. No maintenance is ordinarily required
except the routine removal of dirt and debris from the outside surface of the fins. McQuay
recommends the use of foaming coil cleaners available at most air conditioning supply outlets. Use
caution when applying such cleaners as they may contain potentially harmful chemicals. Care should
be taken not to damage the fins during cleaning.
If the service technician has reason to believe that the refrigerant circuit contains noncondensables,
purging may be required strictly following Clean Air Act regulations governing refrigerant discharge
to the atmosphere. The purge Schrader valve is located on the vertical coil header on both sides of
the unit at the control box end of the coil. Access panels are located at the end of the condenser coil
directly behind the control panel. Purge with the unit off, after shutdown of 15 minutes or longer, to
allow air to collect at the top of the coil. Restart and run the unit for a brief period. If necessary, shut
unit off and repeat the procedure. Follow accepted environmentally sound practices when removing
refrigerant from the unit.
Refrigerant Sightglass
The refrigerant sightglasses should be observed periodically. (A weekly observation should be
adequate.) A clear glass of liquid indicates that there is adequate refrigerant charge in the system to
insure proper feed through the expansion valve. Bubbling refrigerant in the sightglass, during stable
run conditions, indicates that the system may be short of refrigerant charge. Refrigerant gas flashing
in the sightglass could also indicate an excessive pressure drop in the liquid line, possibly due to a
clogged filter-drier or a restriction elsewhere in the liquid line. See Table 58 for maximum allowable
pressure drops). If subcooling is low add charge to clear the sightglass. If subcooling is normal (10
°
-
15
°
F) and flashing is visible in the sightglass check the pressure drop across the filter-drier.
Summary of Contents for ACZ 045A
Page 6: ...6 IOMM ACZ AGZ 1 Figure 3 Clearance Requirements...
Page 27: ...IOMM ACZ AGZ 1 27 Figure 12 AGZ AM Single point Connection with FanTrol...
Page 28: ...28 IOMM ACZ AGZ 1 Figure 13 AGZ AM Single point Connection with SpeedTrol...
Page 29: ...IOMM ACZ AGZ 1 29 Figure 14 AGZ AM Unit Control Schematic UNT...
Page 30: ...30 IOMM ACZ AGZ 1 Figure 15 AGZ AM Staging Schematic UNT...
Page 31: ...IOMM ACZ AGZ 1 31 Figure 16 AGZ AM MicroTech Controller Schematic...
Page 32: ...32 IOMM ACZ AGZ 1 Figure 17 AGZ AM Unit Control Schematic MicroTech...
Page 33: ...IOMM ACZ AGZ 1 33 Figure 18 AGZ AM Staging Schematic MicroTech...
Page 34: ...34 IOMM ACZ AGZ 1 Figure 19 ACZ Field Connection Diagram No Capacity Control...
Page 35: ...IOMM ACZ AGZ 1 35 Figure 20 ACZ Field Wiring Diagram Capacity Control Staging...
Page 104: ...Post Office Box 2510 Staunton Virginia 24402 2510 USA 800 432 1342 www mcquay com...
