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SECTION 1 – INSTALLATION
FORM 145.32-IOM5
ISSUE DATE: 04/08/2019
1
DUCTWORK
When installing ductwork, adhere to local codes.
Where possible, minimize duct runs and avoid abrupt
changes in direction. Allow ample access space to
service the coils and change the filters. Perform regu-
lar maintenance on the ducts to increase the unit life,
maintain efficient operation, and reduce the accumula-
tion of dust and debris.
To not exceed the maximum external static values, re-
fer to the blower performance charts in
, engineer duct runs, and acces-
sory pressure drop.
Louver Sizing Guidelines
An important issue in obtaining optimum performance
from indoor air conditioners is proper selection of the
condenser intake and discharge louvers. In practice,
outdoor air-cooled units intake and discharge their
cooling without restriction. However, indoor units
must first overcome the resistance of grilles or louvers
at the outside wall and then the restriction of any inter-
connecting ductwork.
The DSH's indoor air-cooled air conditioners are de-
signed to accommodate the external static pressure loss
associated with properly sized storm proof louvers. A
storm proof louver typically has a free area approxi-
mately 40–45% of the actual louver size. To determine
the free area required for any given unit, adhere to the
following guidelines:
• The size condenser air intakes are for 350–600
feet/minute nominal velocity. The maximum rec-
ommendation is 700 feet/minute.
• The size condenser air discharge is for 1,200–
1,500 feet/minute nominal velocity. The maxi-
mum recommendation is 1,700 feet/minute.
Louvers with higher velocities than stated above can be
employed. This is at the discretion of the engineer or in-
staller provided that the total air pressure drop does not
exceed the capability of the condenser fan and motor.
Low restriction louvers with shallow blade angles can
allow higher face velocities without excessive static
pressure loss. Exceeding the static pressure capability
of the condenser fan results in insufficient condenser air
volume. This causes a loss in system capacity and can
cause compressor shutdown during high ambient peri-
ods. Where applicable in such cases, the installation of
an oversize condenser motor/drive may be considered.
As a general rule, these velocities require
an intake louver sized approximately 1.25
to 1.5 times the dimensions of the duct
connection on the unit, and a discharge
louver sized approximately 1.5 to 2 times
the duct connection dimensions.
To ensure the unit does not short circuit, only use lou-
ver sections that provide different deflection angles
for air discharge and air intake. Protect the unit from
weather such as rain or snow entering through the con-
denser air intake.
Pitch all outdoor air ducts away from the unit and to-
ward the outside wall. Connect all ducts to the unit with
canvas section duct connectors or choose another suit-
able noise and vibration absorbing device.
The manufacturer does not accept any
liability resulting from incorrect installa-
tion of this equipment. Follow installation
instructions carefully.
ELECTRICAL WIRING
Follow local electrical codes when making
electrical connections. Units are completely factory
wired for normal supply voltages (for example,
208-230/460/575V-3Ph-60Hz). Confirm the unit
specifications by checking the nameplate. The factory
wiring terminates in two boxes, one in each section of
the unit. The electrical control boxes are behind the
outer access panels. Each electrical compartment has
its own control cover.
Provide individual power disconnects for each unit or,
in the case of split applications, each section. Install
a secure ground to both evaporator and condenser. If
canvas flexible joints are used on the ductwork, install
a ground wire to the ductwork as well.
The unit requires the installer to provide a 24V thermo-
stat with appropriate heating and cooling stages. The
condenser section electrical cover is installed with wir-
ing diagrams on the inner access door, which must be
opened to read the diagrams.
Disconnect and lock out power when ser-
vicing unit. Unit may start automatically
if power is not disconnected. Failure to do
so may result in personal injury or death
due to electrical shock.
