Lennox O23V Series Installation Instructions Manual page 23

Troubleshooting: Burner runs continuously (too much or too little heat)
Source Procedure
Thermostat Disconnect thermostat
wires at the primary
control.
S
Burner turns off: ther-
mostat circuit faulty.
S
Primary
Burner not turning off:
control
primary control faulty.
Combus- Check burner
tion combustion for CO2,
stack temperature, and
smoke
S
Low CO
10%.
S
High smoke reading
more than a trace.
S
High stack tempera-
ture is more than
550
Oil Pres- Inspect fire and check
sure oil pressure.
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Causes
Shorted or welded thermostat contacts
Stuck thermostat bimetal
Thermostat not level
Shorted thermostat wires
Thermostat out of calibration
Thermostat in cold draft
Defective primary control
Too much combustion air
Air leaks into heat exchanger around
inspection door, etc.
Excessive draft
less than
2
Incorrect burner head adjustment
Dirty or plugged heat exchanger
Insufficient draft
Incorrect burner head adjustment
Too little combustion air
Too little blower air
_
F net.
Dirty or plugged heat exchanger
Dirty blower wheel
Dirty furnace air filters
Restricted or closed registers/dampers
Partially plugged or defective nozzle
Oil pressure too low: less than 100 psi.
search engine
Too much heat
Correction
Repair or replace the thermostat.
Clear obstruction or replace thermostat.
Level thermostat.
Repair short or replace wires.
Replace thermostat.
Correct draft or relocate the thermostat.
Replace the defective primary control.
Too little heat
Reduce combustion air.
Correct cause of air leak.
Adjust barometric draft control for correct draft.
Correct burner head setting.
Clean heat exchanger.
Readjust burner.
Increase draft.
Correct burner setting.
Increase combustion air.
Check for high static pressure.
Check HEAT selector pin per wiring diagram
(figure 18, page 16).
Clean heat exchanger.
Clean blower wheel.
Clean or replace filter.
Readjust registers or dampers.
Replace nozzle.
Increase oil pressure top 100psi.
Page 23