Installation & Operation Manual (2019)
22
Indoor Return Air Grille and Ductwork Installation
Option 1 Option 2
VPRG4/R Return Air Grille with Access Panel
A eld-supplied (25” x 20”) can be mounted inside
the hinged access door. The door can be installed
with the grille oriented at the top of the panel for
improved sound attenuation.
NOTE: All Vert-I-Pak chassis are shipped with a 20” x 14” lter installed. If a different lter holder or location is to be used,
the lter on the chassis MUST be removed.
Ductwork
The supply duct system should be designed using a recognized method such as the equal fraction or velocity reduction
method, using the appropriate duct calculator(s) for the type(s) of duct being used in the system. The duct system should
be designed for a maximum friction rate of .3” water column taking into consideration all ttings, registers and/or diffus-
ers.
NOTE; Do not operate the unit without a supply duct attached. The return air to the Vert-I-Pak unit MUST NOT be ducted
and all units must have a free return air conguration to perform properly.
Field Supplied Return Air Grille
A eld supplied return air grille divorced from the
access panel must have a minimum 250 square
inches of free area.