Harman PF-120 - Motor And Component Location

Harman® • PF-120 Owner’s Manual_R3 • 2014 -___ • 10/1425
3-90-08120c
The Low Draft Pressure Switchisadifferentialpressureswitch
that monitors the negative pressure (Draft) in the rebox. If the
draftbecomestoo lowfor propercombustion, theswitchopens,
cuttingpowertothefeedmotorandtheignitercircuits.Thisswitch
isconnectedintotheAC(highvoltage)wiring.
The Control Board/ESP combination is responsiblefor allhigh
limitsafetycontrol.Thereare2highlimits,onenormaloperation
highlimitandonebackuphighlimit.Thecontrolhasanautomatic
diagnosticcircuit that continuouslymonitors the ESPand Room
Sensorforfaults.Ifafaultshouldoccur,thecontrolsendsastatus
alertandatthesametimetheunitgoesdowntominimumfeed/
minimumburnasasafetycondition.
Low Draft Pressure Switch
Feed Motor
Combustion Motor
B. Motor and Component Location
PF-120 Pellet Furnace Safety Devices
Igniter
Circuit Breaker Box
UPS Connection
NOTE: UPS connection only for
power failure shut down
ESP