Lennox OHR23-105 - Page 23

Page 23
Troubleshooting: Burner Starts and Fires, but Loses Flame and Lock Out on Safety
Source CorrectionCausesCheckProcedure
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.
py
(black & white
leads). If burner
Blower bearings seized Replace bearings and shaft.
leads)
.
If
burner
cycles due to
it 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.