Harman Stove Company Accentra Service Training page 54

Automatic Circuit Board
Dipswitches
DDM Test Port
All Harman automatic pellet stoves now use the same circuit board.
There is a series of switches on the board, (dipswitches), that are set
differently depending on the stove model it is installed onto. Some switches allow
for changing things such as ignition feed cycle, or igniter timing.
Included on the new circuit board is a test port to attach the DDM, Digital
Diagnostic Meter.
Harman Pellet Service Training 54