Harman PF-120 - Comprehensive Troubleshooting Guide

Harman® • PF-120 Installation Manual_R1 • 2014 -___ • 03/1423
3-90-08121i
DO NOT CONNECT TO A DOWN FLOW FURNACE.
DO NOT CONNECT DUCTWORK SO THAT A REVERSE
FLOW IS POSSIBLE.
Recommendations for Supply Air and Return Air duct
sizing.
Thespeedorvelocityofairmovingthroughductsystems
increasesastheductdecreasesinsizewiththesameCFM
blower.Thesoundofairowingthroughtheductincreases
as the velocity increases. Therefore the largest duct size
practicalshouldbeused.
Thevelocitytosoundlevelmustbetakenintoconsideration
whenconnectingthisfurnaceintoanexistingductsystem.
Asaprimarysourcefurnacetheductsystemcanbeinstalled
totthecustomersneeds.
Velocity 500fpm 700fpm 900fpm
Static-In. W.C. .3Minimumto.6Maximum
1638cfm 470in²  360in²  290in²
(Theseductsizesareonlyrecommendations.)
TheReturnAirductsystemshouldbesizedapproximately
10percentlargerforheatingonlysystemsand20percent
largerifairconditioningisinstalled.
Regardless of the supply air duct size installed, the
DistributionBlowerMotorMUSTbecheckedforrunning
Amperage.Checkthemotornameplateforthefullload
AMPS.Iftheamperageisrunninghigherthanthatlisted,a
supplyairrestrictingdampermayberequiredtoincrease
thesupplyplenumpositivestaticpressure.
NOTE:
It is highly recommended that the furnace
controlbeturnedtothe“OFF”positionwhen
airconditioningisbeingused,whetherornot
itisinterconnected.
CAUTION
!