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Unit coil piping
Chilled water
Unit chilled water coils have a fin height of 48" (1219 mm). A
factory installed three-way valve, piping and motor actuator
is available for chilled water coils provided in a cooling only
section (see Figure 13). When no factory piping or valve is
included, coil connections are 2.50" male NPT copper. With
the factory valve package, field connections are the same
NPT as the valve with female threading. Note: The valve
actuator spring returns to a stem up position upon power
failure. This allows full flow through the coil.
Figure 13. Three-way valve package
Return
Bypass
Supply
Figure 14. Valve assembly
Evaporator
Unit evaporator coils have a fin height of 48" (1219 mm).
Table 9 provides field sweat connection information for
evaporator coils.
Table 9. Unit DX connections
CONNECTION SIZE (IN.)
UNIT DX COIL
LIQUID
SUCTION
RDS 800C
1.375 ODM
2.125 ODS
RDS 802C
1.125 ODM
1.625 ODS
Hot water
Note: If the unit is equipped with an iron valve, connecting to
a copper piping system will likely cause galvanic corrosion to
occur and the valve will not last. All coils have vents and
drains factory installed.
Hot water coils are not normally recommended for use
with entering air temperatures below 40
°
F (4
°
C). No control
system can guarantee a 100% safeguard against coil freeze-
up. Glycol solutions or brines are the only freeze-safe media
for operation of water coils at low entering air temperature
conditions.
Unit hot water coils have a fin height of 39" (991 mm). A
factory installed three-way valve, piping and motor actuator
is available for hot water coils in a heating only section (see
Figure 13). When no factory piping or valve is included, the
coil connections are 1.625" ODM copper. With the factory
valve package, field connections are the same NPT as the
valve with female threading.
Note: The valve actuator spring returns to a stem down
position upon power failure. This allows full flow through the coil.
Coil freeze possible. May damage equipment.
Carefully read instruction for mixing antifreeze solution
used. Some products will have higher freezing points in
their natural state than when mixed with water. The
freezing of coils is not the responsibility of McQuay
International. Refer to “Winterizing Coils” in the “Main-
tenance” section of this manual.
Steam
Unit steam coils have a fin height of 39" (991 mm). A factory
installed two-way valve, piping and motor actuator is avail-
able for steam coils in a heating only section (see Figure 15).
When no factory piping or valve is included, the coil connec-
tions are 2.50" MPT iron pipe. With the factory valve pack-
age, field connections are the same NPT as the valve with
female threading.
Note: The valve actuator spring returns to a stem up
position upon power failure. This allows full flow through the coil.
Steam piping recommendations
Figure 15. Two-way valve package
Supply
Return
1. Be certain that adequate piping flexibility is provided.
Stresses resulting from expansion of closely coupled
piping and coil arrangement can cause serious damage.
Setscrews
Stem
Stem Clip
!
WARNING
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