IOM 1206-7 • TRAILBLAZER
™
MODEL AGZ CHILLERS 98 www.DaikinApplied.com
UnIT maInTenanCe
Filter-Driers
Replace the lter-drier any time excessive pressure drop is
read across the lter-drier and/or when bubbles occur in the
sight glass with normal subcooling. The lter-drier should also
be changed if the moisture indicating liquid line sight glass
indicates excess moisture in the system.
Any residual particles from the condenser tubing, compressor
and miscellaneous components are swept by the refrigerant
into the liquid line and are caught by the lter-drier.
Battery
The controller has a battery located behind the clear
plastic bezel. It is a BR2032 with a minimum life of 2 years
unpowered. The typical battery life is 10 years. .
Liquid Line Solenoid Valve
The liquid line solenoid valves that shut off refrigerant ow
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.
System Adjustment
To maintain peak performance at full load operation, the
system superheat and liquid subcooling may require
adjustment. Read the following subsections closely to
determine if adjustment is required.
Liquid Line Sight Glass
The refrigerant sight glasses should be observed periodically. A
clear glass of liquid indicates that there is subcooled refrigerant
charge in the system. Bubbling refrigerant in the sight glass,
during stable run conditions, may indicates that the system can
be short of refrigerant charge. However, it is not unusual to
see bubbles in the sight glass during changing load conditions.
Refrigerant gas ashing in the sight glass could also indicate
an excessive pressure drop in the liquid line, possibly due to a
clogged lter-drier or a restriction elsewhere in the liquid line.
An element inside the sight glass indicates the moisture
condition corresponding to a given element color. Immediately
after the system has been opened for service, the element may
indicate a wet condition. If the sight glass does not indicate
a dry condition after about 12 hours of operation, the circuit
should be pumped down and the lter-drier changed or verify
moisture content by performing an acid test on the compressor
oil.
Expansion Valve
The expansion valve’s function is to keep the evaporator
supplied with the proper amount of refrigerant to satisfy the
load conditions.
Before adjusting superheat, check that unit charge is correct
and liquid line sight glass is full with no bubbles and that the
circuit is operating under stable, full load conditions.
The suction superheat for the suction leaving the evaporator is
set at the factory to 10 degrees F.
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