Daikin Trailblazer AGZ030-101E Installation, Operation And Maintenance Manual page 110

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.
Battery
The controller has included with it a battery (BR2032) with
a ~2 year life; therefor, it is recommended to include battery
replacement every 2 years in your maintenance plan.
Electrical Terminals
Electric shock hazard. Turn off all power before continuing
with following service.
High Ambient Control Panel
This option consists of an exhaust fan with rain hood, two inlet
screens with filters, necessary controls and wiring to allow
operation to 125°F (52°C). The components can be factory or
field installed as a kit.
• It must be supplied on units operating at ambient
temperatures of 105°F (40.6°C) and above.
• It is automatically included on units with fan VFD (low
ambient option).
• Check inlet filters periodically and clean as required.
Verify that the fan is operational.
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 and Subcooling
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 flashing in the sight glass 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.
If the unit is at steady full load operation and bubbles are
visible in the sight glass, then check liquid subcooling. If
subcooling is low, add charge to clear the sight glass - see
"Refrigerant Charging" on page
filled, extra charge will not lower the liquid temperature and
does not help system capacity or efficiency. If subcooling is
normal (15 to 20 degrees F at full load) and flashing is visible in
the sight glass, check the pressure drop across the filter-drier.
IOM 1206-13 • TRAILBLAZER
DANGER
113. Once the subcooler is
MODEL AGZ CHILLERS
®
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 filter-drier changed or verify
moisture content by performing an acid test on 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.
Thermal Expansion Valve - The suction superheat for the
suction leaving the evaporator is set at the factory to 10
degrees F.
Electronic Expansion Valve - For suction superheat targets,
see "Circuit Level Set Points" on page 60
Filter-Driers
Replace the filter-drier any time excessive pressure drop is
read across the filter-drier and/or when bubbles occur in the
sight glass with normal subcooling. The filter-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 filter-drier.
A condenser liquid line service valve is provided for isolating
the charge in the condenser, but also serves as the point from
which the liquid line can be pumped out. With the line free of
refrigerant, the filter-drier core(s) can be easily replaced.
For units with replaceable core filter driers, the core assembly
of the replaceable core drier consists of a filter core held tightly
in the shell in a manner that allows full flow without bypass.
110
Unit Maintenance
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