882108-YIM-B-1012
Johnson Controls Unitary Products 13
DUCTWORK
Ductwork should be designed and sized according to the
methods in Manual Q of the Air Conditioning Contractors of
America (ACCA).
A closed return duct system should be used. This will not pre-
clude use of economizers or outdoor fresh air intake. The
supply and return air duct connections at the unit should be
made with flexible joints to minimize noise.
When the unit is equipped with power exhaust fans or return
air fan the return duct should have a 90 elbow before opening
to the building space to abate noise.
The supply and return air duct systems should be designed
for the CFM and static pressure requirements of the job. They
should NOT be sized to match the dimensions of the duct
connections on the unit.
If the unit is equipped with hot water or steam heat then the
supply air direction will be down only.
AIR HOODS FOR FIXED OUTSIDE AIR(UNITS WITH MANUAL ECONOMIZER)
These hoods are factory installed. The dampers may be
adjusted by loosening the thumb screw, turning the lever to
the desired position, and retightening the thumb screw.
AIR HOODS FOR ECONOMIZER
There are (3) economizer outside air intake hoods provided
with the unit. The hood on the end of the unit is factory
mounted. The (2) front and rear hoods are made operational
per the following instructions.
Remove the screws holding the economizer hood shipping
covers in place. Discard covers.
Rotate the hoods out (each hood is hinged in the lower cor-
ner). Secure the hoods with screws along the top and sides.
Apply a bead of RTV sealer along the edge of both hoods
and each pivot joint to prevent water leakage.
Seal any unused screw holes with RTV or by replacing the
screw.
AIR HOODS FOR EXHAUST AIR
When furnished, these hoods and dampers are factory
installed.
CONDENSATE DRAIN
There is one condensate drain connection. Trap the connec-
tion per Figure 4. The trap and drain lines should be pro-
tected from freezing.
Plumbing must conform to local codes. Use a sealing com-
pound on male pipe threads. Install condensate drain lines
from the 1-1/2 inch NPT female connections on the unit to an
open drain.
(GAS HEATING OPERATION)
Excessive exposure to contaminated combustion
air will result in safety and performance related
problems. To maintain combustion air quality, the
recommended source of combustion air is the out-
door air supply.
The outdoor air supplied for combustion should be
free from contaminants due to chemical exposure
that may be present from the following sources:
• Commercial buildings
• Indoor pools
• Laundry rooms
• Hobby or craft rooms
• Chemical storage areas
The following substances should be avoided to
maintain outdoor combustion air quality:
• Permanent wave solutions
• Chlorinated waxes and cleaners
• Chlorine based swimming pool cleaners
• Water softening chemicals
• De-icing salts or chemicals
• Carbon tetrachloride
• Halogen type refrigerants
• Cleaning solvents (such as perchloroethylene)
• Printing inks, paint removers, varnishes, etc.
• Hydrochloric acid
• Cements and glues
• Antistatic fabric softeners for clothes dryers
• Masonry acid washing materials