Nortek B6BM Series, Installation Instructions Manual

5

•  Use transition fittings if the supply and/or return air openings 

of the unit do not match the duct openings. These transitions 

should be dimensioned in accordance with standard 

practice as specified in the ASHRAE recommendations 

for duct transitions.

•  Flexible connectors may be used between the unit and the 

ductwork to prevent transmission of vibration from the unit 

to the structure. If electric heater kits are installed, heat 

resistant material must be used for the flexible connector 

at the supply air end of the unit.

•  It is good practice to seal all connections and joints with 

industrial grade sealing tape or liquid sealant. Requirements 

for sealing ducts vary from region to region. Consult with 

local codes for requirements specific to your area.

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.

Air Filters

B6 Series Air Handlers are not supplied with an air filter 

when shipped from the factory. The installer must provide 

a high velocity filter that is appropriately sized to the return 

air duct opening or filter rack located in the bottom of the 

unit. Accessing the filter does not require tools and can be 

removed from the front of the unit by removing the filter 

door. See Unit Maintenance (

page 14

) for filter sizes and 

installation information.

 WARNING:

Never operate the air handler without a filter 

or with doors removed. Dust and lint can build 

up on internal components, resulting in loss of 

efficiency, equipment damage, and possible fire.

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.

•  Damping  ducts,  flexible  vibration  isolators,  or  pleated 

media-style filters on the return air inlet of the air handler 

may be used to reduce the transmission of equipment 

noise eminating from the air handler. These treatments 

can produce a quieter installation, particularly in the 

heated space. However, they can increase the pressure 

drop in the duct system. Care must be taken to maintain 

the proper maximum pressure rise across the air handler, 

temperature rise and flow rate. This may mean increasing 

the duct size and/or reducing the blower speed. These 

treatments must be constructed and installed in accordance 

with NFPA and SMACNA construction standards. Consult 

with local codes for special requirements. For best sound 

performance, be sure to install all the needed gaskets and 

grommets around penetrations into the air handler, such 

as for electrical wiring.

AIR HANDLER INStALLAtIoN

B6 series air handler’s are shipped ready for vertical upflow 

installation and are approved for attic, basement, alcove/closet 

or crawlspace installation with zero clearance to combustibles. 

See 

Table 1, (page 4)

 for required installation clearances. 

this appliance is approved only for indoor use.
•  The unit must be leveled at installation and attached to a 

properly installed duct system.

•  The surface that the air handler is mounted on must provide 

sound physical support of the unit.

•  The  air  handler  must  be  installed  so  that  all  electrical 

components are protected from water.

•  If a louvered door is installed across the front of this unit, 

the appliance must be mounted flush or behind front edge 

of finished wall.

•  Always reinstall the doors on the air handler after servicing 

or cleaning/changing the filters. 

Do not operate the air 

handler without all doors and covers in place.

Packaging Removal

Remove the shipping carton and User’s Manual from the 

equipment. When removing the crate, use extra care so 

tubing connections are not damaged. Do not pull on the 

coils upper tubes.

Mounting Applications

Vertical only air handlers are factory ready for upflow 

applications. These units may be applied in downflow 

applications when applied with the appropriate field kit.
Factory ready horizontal air handlers may be applied in 

upflow or horizontal-left and -right discharge applications. 

These units may also be applied in downflow discharge when 

applied with the appropriate field kit as specified in the units 

Technical Specifications.
Through-the-floor installations require a 1/4” thick 

noncombustible resilient gasket to be used whenever the 

supply or return air ducts pass through the floor. The gasket 

should be positioned between the duct, unit, and floor.

upflow Installations

All air handlers are factory shipped, ready for upflow 

installation. The horizontal drain pan may be removed from the 

air handler when installing the unit in an upflow configuration. 

All return air must enter from the bottom of the unit. A typical 

upflow unit is shown in 

Figure 1 (page 6)

.

Downflow Installations

The downflow accessory kit (See Technical Specifications) is 

required for downflow applications. Instructions for installing 

the downflow accessory kit are included with the kit. It is 

recommended that the accessory be installed prior to installing 

the unit. All return air in downflow applications must enter 

through the top of the unit. A typical installation of the unit 

in a downflow application is shown in 

Figure 2 (page 6)

.

Horizontal Installations

The B6 Series air handler can be installed horizontally in 

an attic, basement, crawl space or alcove. It can also be 

suspended from a ceiling in a basement or utility room in 

either a right to left airflow or left to right airflow as shown in 

Figure 3 (page 6)

. Air handlers may or may not be shipped 

from the factory with all the parts required for horizontal left 

applications and horizontal right applications. If your unit 

does not have parts for a horizontal application, a kit may 

be available.
NotE 1: In all horizontal applications in which the unit is 

installed above a finished ceiling and/or living space, a 

secondary drain pan must be installed under the entire unit