Product manual

McQuay IM 782-4 13
Installation Guidelines
Piping and Coils
Follow applicable piping design, sizing, and installation
information presented in ASHRAE Handbooks in the design
and installation of piping. Observe all local codes and industry
standards. Do not apply undue stress at the connection to the
coil headers. Support pipe work independently of the coils.
Water Cooling Coils
Water cooling coil guidelines are listed below. Refer to
Figure 10.
1 Water supply, water return, drain, and vent connections
extend through the end panel of the coil section. All
connections are labeled on the end panel.
2 Water supply and water return connections are copper
sweat on units 002 through 010 and male NPT iron pipe
on units 015 through 030.
3 When installing couplings, do not apply undue stress to
the connection extending through unit panel. Use a
backup pipe wrench to avoid breaking the weld
between coil connection and header.
4 Follow recommendations of the control manufacturer
regarding types, sizing, and installation of controls.
Figure 14: Water Cooling Coil Connections
Direct Expansion Coils
Direct expansion coil connection guidelines are listed below.
Refer to Figure 11.
1 The coil distributor and suction connection extend
through the end panel of the coil section.
2 Check nozzle in distributor for proper tonnage.
3 The thermostat expansion valve must be an external
equalizer tube type. Connect the equalizer tube provided
on the coil (3/16" for units 002 to 010, and 1/4" for units
015 to 030) to the connection on the expansion valve.
4 Use care when piping up the system, making sure all
joints are tight and all lines are dry and free of foreign
material. For typical refrigerant piping, see the
condensing unit product manual.
Figure 15: DX Coil Connections
Steam Coils (provided as Specials only)
Steam coil connection guidelines are listed below. Refer to
Figure 12.
1 All steam coils in units are pitched toward the return
connection.
2 Steam supply and steam return connections are typically
male NPT iron pipe and are labeled on the end panel of
coil section. Connections extend through coil section end
panel.
3 When installing couplings, do not apply undue stress to
the connection extending through unit panel. Use a
backup pipe wrench to avoid breaking the weld between
coil connection and header.
4 Support piping independently of coils and provide
adequate piping flexibility. Stresses resulting from
expansion of closely coupled piping can cause serious
damage.
5 Do not reduce pipe size at the coil return connection.
Carry return connection size through the dirt pocket,
making the reduction at the branch leading to the trap.
6 Install vacuum breakers on all applications to prevent
retaining condensate in the coil. Connect the vacuum
breaker between the coil inlet and the return main.
7 Do not drip supply mains through the coil.
8 Do not attempt to lift condensate when using modulating
or on/off control.
9 Size traps in accordance with manufacturers’
recommendations. Be certain the required pressure
differential will always be available. Do not undersize.
LH
AIR
FLOW
AIR
FLOW
RH
SUPPLY
RETURN
Left Hand AIr Flow Coil
Right Hand AIr Flow Coil
LH
AIR
FLOW
AIR
FLOW
RH
SUCTION
CONNECTION
SUCTION
CONNECTION
SUCTION
CONNECTION
LIQUID
CONNECTION
Left Hand
Air Flow Coil
Left Hand
Air Flow Coil
Right Hand
Air Flow Coil
Right Hand
Air Flow Coil
LH
AIR
FLOW
AIR
FLOW
RH
LIQUID
CONNECTION
LIQUID
CONNECTION