Furnace Installation and Owners Manual
23
LDJ620_E01_R03_2006.03
Models LDJ620-9 and LDJ620-10
Mechanical / Electrical
Problem
Explanation
What to do
Furnace auger, bin
auger, and combus-
tion fan all do not
operate
High limit switch defective or discon-
nected. All power for the furnace auger,
bin auger, and combustion fan is supplied
through the High Limit Switch.
Verify power to high limit switch.
Verify high limit switch is closed when
furnace is cool.
Combustion fan will
operate but furnace
auger and bin auger,
do not operate
Variable input timer defective.
Check variable input timer.
Low limit switch defective.
Check low limit switch.
Defective heat relay or no HEAT signal
from thermostat or defective 24V trans-
former.
Verify that transformer is okay.
Verify HEAT signal from thermostat.
Check heat relay.
The START/OFF/ON switch left in START
position after starting fire in burn pot.
Change switch to ON.
Blower fan doesn’t
operate
Fan control switch defective; no fire in fur-
nace. Blower for furnace operation (usu-
ally ‘MED’ motor speed) won’t run until fan
control switch senses higher temperature.
Check fan control switch.
Restart fire in burn pot.
Fan relay contacts defective.
Check fan relay.
Blower motor defective.
Replace blower motor.
