Removing Shipping Restraints; Refrigerant Piping-Pressure Relief Valves; Water Connections - McQuay SWP Series Installation And Maintenance Manual

Removing Shipping Restraints

Mechanical restraints are used to secure the spring-mounted
fan during shipment. Remove the restraints and the shipping
blocks after the unit is set in its final location.
Connection plates can be used as rigging plates for the fan
section only. Do not use them for rigging the entire unit.
Unit can tip or fall and cause equipment damage, severe
personal injury, or death.
Refrigerant Piping—Pressure Relief Valves
All units have individual refrigerant circuits and each circuit is
provided with a spring loaded relief valve. The valve is set to
open when refrigerant pressure reaches 400 psig. The relief
valve accommodates a 1/2" flare connection for applications
where it is necessary to connect vent piping and run it outside
the building.
When refrigerant is vented to the outside of the building, install
the vent piping as recommended in ASHRAE Standard
15-1994. Failure to vent properly can result in personal injury.

Water Connections

General
Due to the variety of piping practices, follow the
recommendations of local authorities. They can supply the
installer with the proper building and safety codes required for
proper installation.
For best performance, install the piping with a minimum
number of bends and elevation changes. Size piping to
minimize system pressure drop.
Piping should contain the following:
Vibration eliminators to reduce vibration and noise
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transmission to the building.
Shutoff valves to isolate the unit from the piping system
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during unit servicing.
Manual or automatic air vent valves at the high points of
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the system.
Some means of maintaining adequate system water
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pressure (e.g., expansion tank or regulating valve).
Temperature and pressure indicators located at the unit to
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aid in servicing.
McQuay IM 937
WARNING
CAUTION
A strainer or some means of removing foreign matter,
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which can damage the pump and shorten unit life, from the
water before it enters the pump. Such damage is not
covered by warranty. Place the strainer far enough
upstream to prevent cavitation at the pump inlet (consult
pump manufacturer for recommendations). Using a strainer
prolongs pump life and helps maintain system
performance.
Condenser Piping
Units can be specified with water and condensate
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connections on either the left or right side of the unit.
All condensers are factory piped for a common condenser
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water supply and a common condenser water return
connection.
Make field piping connections to factory-provided piping,
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locating them as indicated on the unit submittal drawings.
Run the piping connections to the outside of the unit
cabinet. Connections are located behind a factory-mounted
shipping cover. All connections are copper sweat
connections as indicated on unit dimensional drawings.
Make supply and return water connections at the proper
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locations as indicated by the dimensional drawings. The
supply (water in) connection is always the lower
connection.
Units with factory-mounted water side economizer should
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not require head pressure control. The economizer typically
elevates the water temperature by 5°F to 10°F before
entering the condenser. Economizer cooling takes over
when the water is too cold for compressor operation.
Mechanical cooling is locked out below 55°F EWT.
If entering condenser water temperatures will go below
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55°F, provide head pressure control. Fan cycling and/or
modulating discharge dampers on the cooling tower are
often used, or a 3-way bypass around the tower is used to
maintain condenser water temperature. If multiple units are
in the loop, it is generally more cost effective to use cooling
tower control to maintain the temperature at >55°F.
If a field-installed water regulating valve is placed in
service with the unit condenser, install it in the water line
leaving the condenser; it should shut down to prevent water
from siphoning out of the condensers. For systems where a
constant pumping head is required, install the water
regulating valve in a bypass line around the condensers. It
then must open on falling discharge pressure.
These typical systems, depending on the specific
application, must maintain a constant condensing pressure
regardless of temperature conditions and must provide
adequate head pressure for proper thermostatic expansion
valve operation. A minimum head pressure of 180 psi
(95°F condensing temperature) is recommended.
Condenser tube velocities must not exceed 10 feet per
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second. Flow and velocity will be satisfactory if water
volumes do not exceed those shown in Table 2 on page 9.
Installation
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