Harman®  •  P-Series Owner’s Manual_R23  •  2014 - ___  •  02/1923 3-90-436168c
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 
isconnectedintotheAC(highvoltage)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. 
Backdraft Damper Assembly
Always check to see if the damper 
plate swings freely inward and that 
the seating edges are not covered 
with dirt or lint.
Low Draft Pressure Switch
Feed Motor
Combustion Motor
B. Motor and Component Location
P-Series Pellet Stove Safety Devices
Distribution Blower