577C--C, 577C--E, 577C--F: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
11
8. Check for gas leaks at the field-installed and factory-installed gas
lines after all piping connections have been completed. Use a
commercially available soap solution (or method specified by local
codes and/or regulations).
Step 9 – Install Duct Connections
The unit has duct flanges on the supply- and return-air openings on the
side and bottom of the unit. For downshot applications, the ductwork
connects to the roof curb (See
for connection sizes and
locations).
Configuring Units for Downflow (Vertical)
Discharge
1. Open all electrical disconnects before starting any service work.
2. Remove horizontal (metal) duct covers to access vertical
(downflow) discharge duct knockouts in unit basepan. (See
.)
3. For single-phase models only, on the discharge side only, remove
the insulation covering the downshot (plastic) knockout. Insulation
is held in place with aluminum tape. Please note that large chassis
units have 2 pieces of insulation, and only the piece over the
downshot knockout needs to be removed. Discard insulation.
4. To remove the downshot (plastic) knockouts for both supply and
returns, break front and right side connecting tabs with a
screwdriver and hammer. Push cover down to break rear and left
side tabs. These plastic knockouts are held in place with tabs
similar to an electrical knockout. Discard plastic knockout covers.
5. Set unit on roof curb.
6. Verify that the downshot ducts are aligned with the downshot
knockout areas.
7. Re-install horizontal (metal) covers as needed to seal unit. Ensure
openings are air and watertight.
NOTE:
The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
nonresidence-type air conditioning and ventilating systems, NFPA 90A
or residence-type, NFPA 90B; and/or local codes and ordinances.
A09061
A09088
Fig. 9 – Supply and Return Duct Opening
Adhere to the following criteria when selecting, sizing, and installing the
duct system:
1. Units are shipped for horizontal duct installation (by removing duct
covers).
2. Select and size ductwork, supply-air registers, and return-air grilles
according to American Society of Heating, Refrigeration and Air
Conditioning Engineers (ASHRAE) recommendations.
3. Use flexible transition between rigid ductwork and unit to prevent
transmission of vibration. The transition may be screwed or bolted
to duct flanges. Use suitable gaskets to ensure weather-tight and
airtight seal.
4. All units must have field-supplied filters or accessory filter rack
installed in the return-air side of the unit. Recommended sizes for
filters are shown in
5. Size all ductwork for maximum required airflow (either heating or
cooling) for unit being installed. Avoid abrupt duct size increases or
decreases or performance may be affected.
6. Adequately insulate and weatherproof all ductwork located
outdoors. Insulate ducts passing through unconditioned space, and
WARNING
!
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death
and/or property damage.
-
Connect gas pipe to unit using a backup wrench to avoid
damaging gas controls.
-
Never purge a gas line into a combustion chamber. Never test
for gas leaks with an open flame. Use a commercially available
soap solution made specifically for the detection of leaks to
check all connections. A fire or explosion may result causing
property damage, personal injury or loss of life.
-
Use proper length of pipe to avoid stress on gas control
manifold.
-
If a flexible connector is required or allowed by authority
having jurisdiction, black iron pipe shall be installed at furnace
gas valve and extend a minimum of 2 in. (51 mm) outside
furnace casing.
-
If codes allow a flexible connector, always use a new connector.
Do not use a connector which has previously serviced another
gas appliance.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Before installing or servicing system, always turn off main power to
system and install lockout tag. There may be more than one disconnect
switch.
CAUTION
!
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in property damage.
Collect ALL screws that were removed. Do not leave screws on rooftop
as permanent damage to the roof may occur.
Horizontal Duct Covers
Basepan
Downflow
(Vertical)
Supply
Knockout
Basepan
Downflow
(Vertical)
Return
Knockout
