Daikin WGZ030DW, Installation, Operation And Maintenance Manual

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IOM 1322-1 • WATER-COOLED SCROLL COMPRESSOR 8 www.DaikinApplied.com
Application Considerations
Chilled Water Piping
Guidelines
Due to the variety of piping practices, it is advisable to follow
the recommendations of local codes for compliance. They
can supply the installer with the proper building and safety
guidelines required for a safe and proper installation
The piping should be designed with a minimum number of
bends and changes in elevation to keep system cost down and
performance up.
WARNING
Polyolester Oil, commonly known as POE oil is a synthetic oil used in many
refrigeration systems, and may be present in this Daikin product. POE oil, if
ever in contact with PVC/CPVC, will coat the inside wall of PVC/CPVC pipe
causing environmental stress fractures.
Although there is no PVC/CPVC piping in this product, please keep this
in mind when selecting piping materials for your application, as system
failure and property damage could result. Refer to the pipe manufacturer’s
recommendations to determine suitable applications of the pipe.
Field installed water piping to the chiller
must
include:
• A cleanable strainer installed at the water inlet to the
evaporator to remove debris and impurities before they
reach the evaporator. Install cleanable strainer within 5
feet (1500 mm) of pipe length from the evaporator inlet
connection and downstream of any welded connections
(no welded connections between strainer and evaporator
WGZ-D models with braze plate evaporators require a
strainer with perforations no larger than 0.063” (1.6 mm)
diameter. Models with shell and tube evaporators require
a strainer with perforations no larger than 0.125” (3.2
mm) diameter.
• A water flow switch must be installed in the horizontal
piping of the evaporator outlet. The flow switch may be
ordered as a factory-installed option, a filed-installed kit,or
may be supplied and installed in the field. See page 10
for further information regarding flow switches.
• All piping should be installed and supported to prevent
the chiller connections from bearing any strain or weight
of the system piping.
• Manual or automatic air vent valves at the high points of
the system. Drains should be placed at the lowest points
in the system. Braze plate evaporators do not have vent
or drain connections and provisions must be made in the
entering and leaving chilled water piping for venting and
draining.
• Chilled water piping must be insulated to reduce heat
loss and prevent condensation per code requirements.
Complete unit and system leak tests should be performed
prior to insulating the water piping. Insulation with a vapor
barrier would be the recommended type of insulation.
The vent and drain connections must extend beyond the
proposed insulation thickness for accessibility.
It is recommended that the field installed water piping to the
chiller include:
• Some means of maintaining adequate system water
pressure (e.g., expansion tank or regulating valve).
• Temperature and pressure indicators located within 3 feet
(0.9 meters) of the inlet and outlet of the vessels to aid in
unit servicing. Pressure drop through the vessel should
be measured to determine water flow from the flow
pressure drop curves beginning on page 13 .
• Flush the system thoroughly prior to unit installation.
• A preliminary leak check of the water piping should be
made before filling the system.
• Vibration eliminators to reduce vibration and noise
transmission to the building.
• Shutoff valves to isolate the unit from the piping system
during unit servicing.
• Regular water analysis and chemical water treatment
on the evaporator is recommended immediately upon
equipment start-up.
• Chillers not run in the winter should have their water
systems thoroughly drained if subject to sub-freezing
temperatures. If the chiller operates year-round, or if the
system is not drained for the winter, the chilled water
piping exposed to sub-freezing ambient temperatures
should be protected against freezing by wrapping the
lines with a heater cable. In addition, an adequate
percentage of glycol should be added to the system
to further protect the system during low ambient
temperature periods. It should be noted that water piping
that has been left drained is subject to more corrosion
than if filled with water. Use of a Vapor Corrosion Inhibitor
(VCI) or some other protection should be considered.
See the section titled “Glycol Solutions” for additional
information concerning the use of glycol.
This product is equipped with a copper-brazed 304 series
stainless steel evaporator plate or a shell and tube evaporator
with carbon steel shell and copper tubes. The water or
other fluid used in these evaporators must be clean and
noncorrosive to the materials used in the evaporator. The use
of non-compatible fluids can void the equipment warranty. If
the compatibility of the fluid with the evaporator is in question,
a professional water quality consultant should administer the
proper testing and evaluate compatibility.
System Water Volume
It is important to have adequate water volume in the system to
provide an opportunity for the chiller to sense a load change,
adjust to the change, and then stabilize. The system water
volume is the total amount of water in the evaporator, air
handling equipment, and associated piping. As the expected
load change becomes more rapid, a greater water volume is
needed. If the water volume is too low, operational problems
can occur including rapid compressor cycling, rapid loading
and unloading of compressors, erratic refrigerant flow in the
chiller, improper motor cooling, shortened equipment life and
other undesirable occurrences.
Application Considerations