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Troubleshooting: Burner fails to start.
Source
Procedure
Causes
Correction
Thermostat in
OFF
or
COOL
Switch to
HEAT
.
Thermostat
Check thermostat settings.
Thermostat is set too low
Turn thermostat to higher tem-
perature.
Burner motor overload tripped
Push reset button pump motor.
Safety Overloads
Check burner motor, primary
safety control, & auxiliary limit
switch
Primary control tripped on safe-
ty
Reset primary control.
switch.
Auxiliary limit switch tripped on
safety
Reset auxiliary limit.
Check furnace disconnect
Open switch
Close switch.
Power
Check furnace disconnect
switch & main disconnect.
Blown fuse or tripped circuit
breaker
Replace fuse or reset circuit
breaker.
Broken or loose thermostat
wires
Repair or replace wires.
Thermostat
Touch jumper wire across ther-
mostat terminals on primary
Loose thermostat screw con-
nection
Tighten connection.
Thermostat
mostat terminals on primary
control. If burner starts, then
fault is in the thermostat circuit.
Dirty thermostat contacts
Clean contacts.
fault is in the thermostat circuit.
Thermostat not level
Level thermostat.
Faulty thermostat
Replace thermostat.
Disconnect the flame detector
i
t th
i
t l If
Flame detector leads are
shorted
Separate leads.
CAD Cell
wires at the primary control. If
the burner starts, fault is in the
Flame detector exposed to light
Seal off false source of light.
the burner starts, fault is in the
detector circuit.
short circuit in the flame detec-
tor
Replace detector.
Primary or auxiliary control
Check adjustment. Set the
maximum setting.
Place trouble light between the
black and white leads. No light
indicates that no power is going
Primary or auxiliary control
switch is open
Jumper terminals; if burner
starts, switch is faulty, replace
control.
Primary Control
indicates that no power is going
to the control.
Open circuit between discon-
nect switch and limit control
Trace wiring and repair or re-
place it.
Low line voltage or power fail-
ure
Call the power company.
Place trouble light between the
orange and white leads. No light
indicates faulty control.
Defective internal control circuit
Replace the control.
Place the trouble light between
the black and white leads to the
burner motor. No light indicates
that no power is getting to the
motor.
Blown fuse
Replace the fuse.
Burner
Place trouble light between the
black and white leads to the
Binding burner blower wheel
Turn off power and rotate the
blower wheel by hand. If seized,
black and white leads to the
blower motor. Light indicates
power to the motor and burner
Sized fuel pump
blower wheel by hand. If seized,
free the wheel or replace the
fuel pump.
power to the motor and burner
fault.
Defective burner motor
Replace the motor.
