Clearance And Return Air Requirements; Airfl Ow Direction And Preparation Before Installation - Fujitsu AIRSTAGE ARUX12TLAV2 Installation Manual

3.3. Clearance and return air requirements

Location
Access for servicing is an important factor in the location of any indoor unit. Provide a
minimum of 30 inches in front of the appliance for access to the control box, heating ele-
ments, fan unit and air filters. This access may be provided by a closet door or by locating
the appliance so that a wall or partition is not less than 30 inches from the front access Panel
Location is usually predetermined. Check with owner's or dealer's installation plans. If loca-
tion has not been decided, consider the following in choosing a suitable location.
(1) Select a location with adequate structural support, space for service access, clearance
for return and supply duct connections.
(2) Normal operating sound levels may be objectionable if the indoor unit is placed directly
over or under some rooms such as bedrooms, study, etc.
(3) Caution should be taken to locate the unit so that supply and return air ducts are about
the same length causing even air distribution of supply and return air to and from the
living spaces.
(4) Locate appliance where electrical supply wiring can be easily routed to main electrical
panel and where electrical wiring will not be damaged.
(5) Locate appliance where remote controller wiring can be easily routed to the remote
controller and where the wiring will not be damaged.
(6) Locate appliance where refrigerant lines can be easily routed from the heat exchanger
to the condenser.
(7) Locate the appliance where condensate lines can be easily routed to an available drain.
Be sure to route condensate drain piping so as not to obstruct access to the air filter.
(8) When the heat exchanger is installed in a draw-thru application it will create a negative
pressure situation in the condensate drain system. To prevent condensate from being
drawn into the fan unit it is recommended to trap the primary (Main) and secondary
(Overflow) drain line. If the secondary drain is not used, it must be capped.
(9) The draw-thru design will cause exterior surface of cabinet to sweat when units is
installed in a non-conditioned space such as an attic or garage. Installer must provide
protection such as full size auxiliary drain pan on all units installed in a non-conditioned
space to prevent damage from condensation runoff.
Some states, cities and counties require additional insulation to be installed on the exte-
rior casing of the indoor unit to prevent sweating. Refer to the state, city, county or local
code for insulation requirement to be sure the installation is in compliance.
It is recommended that indoor units installed in non conditioned spaces be insulated
on the exterior of the entire cabinet, including the front access panel with 1 inch thick
fiberglass with the vapor barrier on the outside.
• Provide a service access for inspection purposes.
• Do not place any wiring or illumination in the service space, as they will impede service.
Duct
1
0 0
Side Side
Return Air
In order for the indoor unit to work properly, a closet or alcove must have a certain total free
area opening for the return air.
Model
ARUX12/18/24 • Minimum 200 in² free area opening
• Use return grille or heat exchanger cabinet
ARUX30/36 • Minimum 250 in² free area opening
• Use return grille, heat exchanger cabinet, or any return grille with a
minimum 250 in² free area opening
ARUX48/60 • Minimum 390 in² free area opening
• Use return grille, or heat exchanger cabinet, or any return grille with a
minimum 390 in² free area opening
Unit: in
Duct
1
Top
0
Front
• Alcove: 30
(access for
service)
• Closet: 6
0
Back
Return air requirements
3.4. Airfl ow direction and preparation before installation
Arrangement:
Unit is shipped from the factory arranged to be installed in an upflow or horizontal right to left
airflow position. Horizontal right to left means, when facing the front of the unit, when the unit
is laid on its side, the supply air opening is to the left and the return opening is to the right.
These models are field convertible to a horizontal left to right airflow position.
3.4.1 Upfl ow application
In an upflow installation the discharge outlet is at the top.
Air
Care should be taken to insure unit is level to permit prop-
er condensate drainage. Normal upflow installation will be
in a closet or basement. If installed in a closet, the closet
should have a platform framed in, that with an opening at
the top of the platform centered in the closet that measure
Control box
at least 12 inches in height. A filter frame and filter can be
used that covers the opening and is sealed to prevent air
by-passing the filter. The minimum filter size is shown in
the table below.
Standard Throw away Air Filter @ 300 ft/min or less
800 CFM = 20 x 20 x 1
Fan unit
1000 CFM = 20 x 25 x 1
1200 CFM = 20 x 30 x 1
1400 CFM = 25 x 30 x 1
1600 CFM = 25 x 30 x 1
1800 CFM = 30 x 30 x 1
2000 CFM = 30 x 40 x 1 or two 30 x 20 x 1
2400 CFM = 30 x 40 x 1 or two 30 x 20 x 1
Pleated Air Filter @ 500 ft/min or less
800 CFM = 16 x 16 x 1
1000 CFM = 18 x 20 x 1
1200 CFM = 20 x 20 x 1
1400 CFM = 20 x 20 x 1
Heat ex-
1600 CFM = 20 x 25 x 1
changer
1800 CFM = 20 x 30 x 1 or two 20 x 15 x 1
2000 CFM = 20 x 30 x 1 or two 20 x 15 x 1
2400 CFM = 25 x 30 x 1 or two 14 x 30 x 1
• Connect the supply air outlet to a plenum to the top of the unit and secure it with screws.
Use a Non-tape sealant such as mastic or an aerosol sealant to seal duct leakage.
• If installed in a basement, run supply and return duct work in accordance with local codes.
3.4.2 Right to left airfl ow application
• This product is shipped to be installed without modification in a right to left airflow configura-
tion.
Control box
Air
Fan unit
• Horizontal flow applications will normally be used in an attic or crawl space. This type of
installation requires supply air plenum or duct to be connected to the supply collar and a
return air plenum or duct be attached to the unit inlet collar. The supply ducts will be con-
nected to the supply air plenum and routed thru the attic to a register in each room. Use a
Non-tape sealant such as mastic or an aerosol sealant to prevent leaks in the ducts and the
plenum.
• The opposite end of the return air duct is attached to a return filter grille housing. The filter
grille is usually located in a wall, just below the ceiling or the ceiling in a hallway. Use a
non-tape sealant such as mastic or an aerosol sealant to prevent leaks in the ducts and the
plenum.
3.4.3 Left to right airfl ow application
Heat ex-
changer
Left to right airflow application require internal configuration changes.
Heat ex-
changer
Control box Air
Fan unit
En-4