403134-YIM-E-0311
12
Johnson Controls Unitary Products
Ductwork
Ductwork should be designed and sized according to the
methods in Manual D of the Air Conditioning Contractors of
America (ACCA) or as recommended by any other recognized
authority such as ASHRAE or SMACNA.
A closed return duct system should be used. This will not
preclude 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.
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.
Refer to Figures 5 and 6 for bottom air duct openings. Refer to
Figure 9 for side air duct openings.
NOTE:
It is recommended that, in Canada, the outlet duct be
provided with a removable access panel. It is
recommended that this opening be accessible when
the unit is installed in service, and of a size such that
smoke or reflected light may be observed inside the
casing to indicate the presence of leaks in the heat
exchanger. The cover should be attached in a manner
adequate to prevent leakage.
Condensate Drain
Plumbing must conform to local codes. Use a sealing compound
on male pipe threads. Install a condensate drain line from the
3/4” NPT female connection on the unit to an open drain.
NOTE:
The condensate drain operates in a negative pressure
in the cabinet. The condensate drain line MUST be
trapped to provide proper drainage. See Figure 11.
Figure 11: Condensate Drain
Compressors
The scroll compressor used in this product is specifically
designed to operate with R-410A Refrigerant and cannot be
interchanged.
The compressor also uses a polyolester (POE oil), Mobil 3MA
POE. This oil is extremely hygroscopic, meaning it absorbs
water readily. POE oil can absorb 15 times as much water as
other oils designed for HCFC and CFC refrigerants. Take all
necessary precautions to avoid exposure of the oil to the
atmosphere.
POE (polyolester) compressor lubricants are known to cause
long term damage to some synthetic roofing materials.
Procedures which risk oil leakage include, but are not limited to,
compressor replacement, repairing refrigerant leaks, replacing
refrigerant components such as filter drier, pressure switch,
metering device or coil.
Units are shipped with compressor mountings which are
factory-adjusted and ready for operation.
Units with scroll compressors have a shipping bracket which
must be removed after the unit is set in place. See Figure 12.
When fastening ductwork to side duct flanges on unit,
insert screws through duct flanges only. DO NOT insert
screws through casing. Outdoor ductwork must be
insulated and water-proofed.
This system uses R-410A Refrigerant which operates at
higher pressures than R-22. No other refrigerant may be
used in this system.
Do not leave the system open to the atmosphere. Unit
damage could occur due to moisture being absorbed by
the
POE oil
in the system. This type of oil is highly
susceptible to moisture absorption
Exposure, even if immediately cleaned up, may cause
embrittlement (leading to cracking) to occur in one year
or more. When performing any service that may risk
exposure of compressor oil to the roof, take precautions
to protect roofing.
