Nortek P94RD Series, Installation Instructions Manual

4

Minimum Clearance Requirements

Sufficient clearance for unobstructed airflow through the outdoor 
coil must be maintained in order to provide room for proper 
servicing and achieve rated performance. See 

Figure 1

 for 

minimum clearances to obstructions.
Service Access Clearance:

Blower and electrical control access panels .............. 24”

Compressor compartment access panel ................... 24”

Clearance from top of unit  ........................................ 72”

Clearance around condenser coil area to

Wall or shrubs (excludes duct panel side) ................. 12”

Clearances to Combustibles:

Combustible base - wood or Class A, B, or C

roof covering material ................................................ 0”

Supply & return air ducts ........................................... 0”

Duct connection side ................................................. 0”

Air Duct System

Air ducts must be installed in accordance with the standards of 

the National Fire Protection Association “Standard for Installation 

of Air Conditioning and Ventilation Systems” (NFPA 90A), 

“Standard for Installation of Residence Type Warm Air Heating 

and Air Conditioning Systems” (NFPA 90B), these instructions, 

and all applicable 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 methods described by the 

Air Conditioning Contractors of America (ACCA).

•  The supply duct system, including the number and type of 

registers, will have much more effect on the performance of 

the system than any other factor. The duct must be sufficiently 

large to conduct an adequate amount of air to each register. 

See 

Figure 2

.

•  Duct work should be attached directly to the unit flanges for 

horizontal applications.

Figure 2. Single & Multiple Duct Applications

MULTIPLE DUCT APPLICATION

SINGLE DUCT APPLICATION

•  For highly resistive duct systems it may be necessary to add 

an additional return air duct and or supply to achieve maximum 

performance and prevent coil icing and refrigerant flood back.

•  The air conditioning output of the system will not cool 

the home if air is lost to the outside through leaks in the 

duct system. Ducts that are collapsed or restricted by 

foreign objects will also prevent adequate air flow.

•  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.

24"

12"

24"

TO

P OF UNIT

TO

 BE

UNOBSTR

UCTED

0"

Figure 1. Minimum Unit Clearances