Daikin AWV008, Инструкция по установке, эксплуатации и обслуживанию

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www.DaikinApplied.com 15 IOM 1242-2 • PATHFINDER
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MODEL AWV CHILLERS
• Thermometers at the inlet and outlet connections of the
evaporator.
• Water pressure gauge connection taps and gauges at
the inlet and outlet connections of the evaporator for
measuring water pressure drop.
• Shutoff valves to isolate the unit from the piping during
unit servicing.
• Minimum bends and changes in elevation to minimize
pressure drop.
• An expansion tank and regulating valve to maintain
adequate water pressure. Tank becomes required
for closed loop systems based on water volume and
temperature ranges.
• Vibration eliminators in both the supply and return water
lines to reduce transmissions to the building.
• Flushing the system water piping thoroughly before
making connections to the unit evaporator.
• Piping insulation, including a vapor barrier, helps prevent
condensation and reduces heat loss.
• Regular water analysis and chemical water treatment
for the evaporator loop is recommended immediately at
equipment startup.
WARNING
Daikin Applied recommends against the use of PVC and
CPVC piping for chilled water systems. In the event the pipe
is exposed to POE oil used in the refrigerant system, the pipe
can be chemically damaged and pipe failure can occur.
Inlet Strainer Guidelines
An inlet water strainer kit must be installed in the chilled water
piping within 5 feet of the evaporator inlet. Two paths are
available to meet this requirement:
1. A field-installed kit shipped loose with the unit is available
for all unit sizes and consists of:
• Y-type area strainer with 304 stainless steel perforated
basket, Grooved pipe connections and strainer cap
— a strainer with perforations no larger than 0.063”
(1/16”, 1.6 mm) diameter for AWV models with a
braze plate evaporator
— a strainer with perforations no larger than 0.125”
(1/8”, 3.2 mm) diameter for AWV models with a direct
expansion evaporator
• Extension pipe with two couplings that may be used
for gauges and sensors. The pipe provides sufficient
clearance from the evaporator for strainer basket
removal.
• ½-inch blowdown valve
• Two grooved clamps
The strainer is sized per Table 2 and has the pressure drop
shown in the Strainer Pressure Drop graph. Connection sizes
are given in the Pressure Drop Data section on page 39 .
2. A field-supplied strainer that meets specification and
installation requirements of this manual.
Table 2: Strainer Sizing Data
Strainer
Size (in.)
Maximum Perforation Size
in. (mm)
Strainer Weight
(lbs)
6 0.063” (1/16”, 1.6 mm) 120
6
0.125” (1/8”, 3.2mm)
120
8 220
10 514
Figure 26: Strainer Pressure Drop
Installing Inlet Strainer (Field-installed Kit)
The extension pipe is located adjacent to the evaporator with
the strainer then mounted to it. The strainer must be mounted
per manufacturer’s instruction with the arrows in the direction
of flow; inlet and outlet are noted along with the arrows.
Use one grooved clamp to mount the extension pipe to the
evaporator and the second to mount the strainer to the pipe.
The clamps to mount the field piping to the strainer are field
supplied. The piping and strainer must be supported to prevent
any stress on the evaporator nozzle.
System Water Volume
All chilled water systems need adequate time to recognize a
load change, respond to that load change and stabilize, without
undesirable short cycling of the compressors or loss of control.
In air conditioning systems, the potential for short cycling
usually exists when the building load falls below the minimum
chiller plant capacity or on close-coupled systems with very
small water volumes. Some of the things the designer should
consider when looking at water volume are the minimum
cooling load, the minimum chiller plant capacity during the low
load period and the desired cycle time for the compressors.
Assuming that there are no sudden load changes and that
the chiller plant has reasonable turndown, a rule of thumb of
“gallons of water volume equal to two to three times the chilled
water gpm flow rate” is often used. A storage tank may have
to be added to the system to reach the recommended system