Lennox SIGNATURE SLO185UFV Series, Installation Instructions Manual

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Page 24
Troubleshooting: Burner fails to start.
Source Procedure Causes Correction
Thermostat Check thermostat settings.
Thermostat in OFF or COOL Switch to HEAT .
Thermostat is set too low
Turn thermostat to higher tem­
perature.
Safety Overloads
Check burner motor, primary
safety control, & auxiliary limit
switch.
Burner motor overload tripped Push reset button pump motor.
Primary control tripped on safe­
ty
Reset primary control.
Auxiliary limit switch tripped on
safety
Reset auxiliary limit.
Power
Check furnace disconnect
switch & main disconnect.
Open switch Close switch.
Blown fuse or tripped circuit
breaker Replace fuse or reset circuit
breaker.
Thermostat
Touch jumper wire across TR-
TW terminals on primary control.
If burner starts, then fault is in
the thermostat circuit.
Broken or loose thermostat
wires
Repair or replace wires.
Loose thermostat screw con­
nection
Tighten connection.
Dirty thermostat contacts Clean contacts.
Thermostat not level Level thermostat.
Faulty thermostat Replace thermostat.
Open circuit in wiring between
ST9103A and oil primary con­
trol. Check wiring between
ST9103A and oil primary con­
trol.
Cad Cell
Disconnect the flame detector
wires at the primary control. If
the burner starts, fault is in the
detector circuit.
Flame detector leads are
shorted
Separate leads.
Flame detector exposed to light Seal off false source of light.
short circuit in the flame detec­
tor
Replace detector.
Primary Control
Place trouble light between the
orange and white leads. No light
indicates that no power is going
to the control.
Primary or auxiliary control
switch is open
Check adjustment. Set the
maximum setting.
Jumper terminals; if burner
starts, switch is faulty, replace
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.
Failed internal control circuit Replace the control.
Burner
Place the trouble light between
the orange and white leads to
the burner motor. No light indi­
cates that no power is getting to
the motor.
Blown fuse Replace the fuse.
Place trouble light between the
black and white leads to the
blower motor. Light indicates
power to the motor and burner
fault.
Binding burner blower wheel
Turn off power and rotate the
blower wheel by hand. If
seized, free the wheel or re­
place the fuel pump.
Seized fuel pump
Failed burner motor Replace the motor.