Service; Liquid Line Solenoid Valve - McQuay AGZXXXBS Series Installation, Operation And Maintenance Manual

Service

familiar with equipment operation, maintenance, correct servicing procedures, and the
Filter-Driers
A replacement of the filter-drier is recommended any time excessive pressure drop is
read across the filter-drier and/or when bubbles occur in the sight glass with normal
subcooling. The maximum recommended pressure drops across the filter-drier are as
follows:
Table 45, Filter-Drier Pressure Drop
The filter-drier should also be changed if the moisture indicating liquid line sight glass
indicates excess moisture in the system.
During the first few months of operation the filter-drier replacement can be necessary if
the pressure drop across the filter-drier exceeds the values listed in the paragraph
above.
miscellaneous components are swept by the refrigerant into the liquid line and are
caught by the filter-drier.

Liquid Line Solenoid Valve

The liquid line solenoid valves that shut off refrigerant flow in the event of a power
failure do not normally require any maintenance. The solenoids can, however, require
replacement of the solenoid coil or of the entire valve assembly.
The solenoid coil can be checked to see that the stem is magnetized when energized by
touching a screwdriver to the top of the stem. If there is no magnetization, either the
coil is bad or there is no power to the coil.
The solenoid coil can be removed from the valve body without opening the refrigerant
piping after pumpdown. For personal safety, shut off and lock out the unit power.
The coil can then be removed from the valve body by simply removing a nut or snap-
ring located at the top of the coil. The coil can then be slipped off its mounting stud for
replacement.
To replace the entire solenoid valve follow the steps involved when changing a filter-
drier.
98
Service on this equipment is to be performed by qualified refrigeration personnel
safety hazards inherent in this work. Causes for repeated tripping of equipment
protection controls must be investigated and corrected.
Disconnect all power before doing any service inside the unit.
Anyone servicing this equipment shall comply with the requirements set forth by the
EPA in regards to refrigerant reclamation and venting.
PERCENT CIRCUIT
LOADING (%) DROP ACROSS FILTER DRIER PSIG (KPA)
100%
75%
50%
25%
Any residual particles from the condenser tubing, compressor and
AGZ 026B through 130B
WARNING
MAXIMUM RECOMMENDED PRESSURE
10 (69)
8 (55.2)
5 (34.5)
4 (27.6)
IOMM AGZ-5