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Troubleshooting: Burner Starts and Fires, but Loses Flame and Lock Out on Safety
Source
Correction
Causes
Check
Procedure
Oil Supply
Listen for pump whine
Restriction in oil line
Clear restriction.
Plugged fuel pump strainer
Clean strainer or replace
pump.
Cold oil − outdoor tank
Change to number 1 oil.
Troubleshooting: Burner starts and fires, but short cycles (too little heat)
Source
Procedure
Causes
Correction
Thermostat
Check thermostat.
Heat anticipator set too low
Correct heat anticipator setting.
Vibration at thermostat
Correct source of vibration.
Thermostat in the path of a warm air
draft
Shield thermostat from draft or
relocate.
Limit Control
Connect voltmeter
bet een line
Dirty furnace air filters
Clean or replace filter.
between line
voltage
connections to
Burner running too slow
Increase blower speed to maintain
proper temp. rise.
connections to
primary control
(bl
k &
hit
Blower motor seized or burned out
Replace motor.
p
y
(black & white
leads). If burner
Blower bearings seized
Replace bearings and shaft.
leads). If burner
cycles due to
i t
ti
Blower wheel dirty
Clean blower wheel.
y
power interruption,
it is cycling on limit
Blower wheel in backward
Reverse blower wheel.
it is cycling on limit.
Wrong motor rotation
Replace with properly rotating wheel.
Restrictions in return or supply air
system
Correct cause of restriction.
Adjustable limit control set too low
Reset limit to maximum stop setting.
Power
If voltage
fluctuates, fault is
in the power
Loose wiring connection
Locate and secure connection.
p
source. Recheck
voltage at the
power source.
Low or fluctuating line voltage
Call power company.
