Table of Contents
Advertisement
CIRCULATING AIR SUPPLY
WARNING:
Products of combustion must not be allowed to
enter the return air ductwork or the circulating air
supply.Failure to prevent products of combustion
from being circulated into the living space can
create potentially hazardous conditions including
carbon monoxide poisoning that could result in
personal injury or death.
All return ductwork must be adequately sealed,
all joints must be taped, and the ductwork must
be secured to the unit with sheet metal screws.
When return air is provided through the bottom
of the unit, the joint between the unit and the
return air plenum must be air tight.
The cement pad that the unit is mounted must
provide sound physical support of the unit with
no gaps, cracks, or sagging bewteen the unit
and pad
Return air and circulating air ductwork must not
be connected to any other heat producing device
such as a fireplace insert, stove, etc. Doing so
may result in fire, explosion, carbon monoxide
poisoning, personal injury, or property damage.
Air Ducts
This unit is designed only for use with a supply and return
duct. Air ducts should be installed in accordance with the
standards of the National Fire Protection Association
"Standard for Installation of Air Conditioning Systems"
(NFPA 90A), "Standard for Installation of Residence Type
Warm Air Heating and Air Conditioning Systems" (NFPA
90B), and all applicable local codes. NFPA publications
are available by writing to: National Fire Protection
Association, Batterymarch Park, Quincy, ME 02269 or
visit www.NFPA.org on the web.
• Design the duct work according to Manual D by the Air
Conditioning Contractors of America (ACCA).
• The ducts must be properly sized not to exceed the
units maximum ESP rating at 400 SCFM per nominal
ton of cooling capacity.
• Duct work should be attached directly to the unit flanges
for horizontal applications.
• It is recommended that the outlet duct be provided
with a removable access panel. The opening should
be accessible when the unit is installed in service and
shall be sizes so that smoke or reflected light may be
observed inside the casing to indicate the presence of
leaks in the heat exchanger. The cover for the opening
shall be attached in a way that will prevent leaks.
Air Filter Requirements
WARNING:
Never operate the unit without a filter in place.
Dust and lint could accumulate on internal parts,
resulting in loss of efficiency,equipment damage
and possible fire.
NOTE TO INSTALLER: After installing or replacing the
filtration system for this unit, add the following statement
on or adjacent to the filter service panel: "Replace
filter(s) installed in your system only with the same
dimensional size filters that are being replaced."
• A suitable air filter must be installed upstream of
the evaporator coil of the return air system. For
recommended external filter sizes, refer to Table 1.
• All return air must pass through the filters before entering
the evaporator coil. It is important that all filters be kept
clean and replaced frequently to ensure proper operation
of unit. Dirty or clogged filters will reduce the efficiency
of the unit and result in unit shutdowns.
• Air filter pressure drop is recommended not to exceed
0.08 inches WC.
NOMINAL
APPROXIMATE
COOLING
AIR FLOW
(TONNAGE)
RANGE (CFM)
2.0
600-900
2.5
750-1200
3.0
1100-1300
3.5
1200-1600
4.0
1400-1800
5.0
1700-2200
* Based on velocity of 300 ft/min for disposable filters.
Table 1. Recommended External Air Filter Sizes
Unconditioned Spaces
All duct work passing through unconditioned space must
be properly insulated to minimize duct losses and prevent
condensation. Use insulation with an outer vapor barrier.
Refer to local codes for insulation material requirements.
Acoustical Duct Work
Certain installations may require the use of acoustical
lining inside the supply duct work.
• Acoustical insulation must be in accordance with the
current revision of the Sheet Metal and Air Conditioning
Contractors National Association (SMACNA) application
standard for duct liners.
• Duct lining must be UL classified batts or blankets with
a fire hazard classification of FHC-25/50 or less.
• Fiber duct work may be used in place of internal duct
liners if the fiber duct work is in accordance with the
current revision of the SMACNA construction standard
on fibrous glass ducts. Fibrous duct work and internal
acoustical lining must be NFPA Class 1 air ducts when
tested per UL Standard 181 for Class 1 ducts.
APPROXIMATE
RECOMMENDED
FILTER AREA
FILTER SIZE
(SQ. IN.)*
(IN. X IN.)
450
20 x 25
550
20 x 30
625
25 x 25
750
24 x 30
850
18 x 24 (2 required)
1000
20 x 25 (2 required)
7
Advertisement
Table of Contents
