Carrier 40RU - Manual (Page 22)

22
Connecting Ductwork -- Refer to the Carrier System
Design Manual for the recommended design and layout of
ductwork. Fig. 19 shows recommended duct connection to
units with 2 fans.
UNIT OPERATION HAZARD
Failure to follow this caution could cause equipment
damage.
Do not operate unit without ductwork or discharge
plenum unless fan speed has been adjusted for
external static pressure of zero in. wg. Failure to do so
may result in motor overload.
CAUTION
!
DISCHARGE CONNECTIONS — Duct flanges are
factory--supplied; they are shipped inside the unit attached to
the hairpin end of the coil tube sheet for field installation.
Using the existing screws, install the duct flanges on the
unit’s fan deck. Each fan discharge requires 2 flanges; each
flange must be bent in the middle to conform to the
discharge opening. See Fig. 20. After flanges are installed,
connect them to the supply duct using a canvas connection
to prevent vibration. It is important that this connection be
properly fabricated to prevent high air friction losses and air
noise.
RETURN CONNECTIONS — When using return--air
ductwork, route return--air duct to the unit’s return air inlet
near the filter rack, using a canvas connection to prevent
transmission of unit vibration. If the duct blocks off the
unit’s access panel, provide a slip joint in the ductwork to
permit removal for servicing.
C10696
Fig. 19 -- Typical Fan Discharge Connections
for Multiple Fan Units
OUTDOOR--AIR INLET CONNECTIONS — Connect
outdoor--air inlet to field--installed accessory economizer.
Refer to Economizer Installation Instructions.
Return--Air Filters -- Type and size of filters are shown in
Tables 1A – 1F and are factory--supplied and
factory--installed. In all units with 2 fans, a filter replacement
tool (hook) is shipped inside the unit for field use when
replacing filters. See the Service section for instructions on
filter element replacement.
C10697
Fig. 20 -- Duct Flange Installation
40RU