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Source Procedure Causes Correction
Burner Motor Low line voltageMotor does not come up to speed
and trips out on overload. Turn off
power and rotate blower wheel by
hand to check for binding or
excessive drag.
Check voltage at power source.
Correct cause of voltage drop or the
call power company.
Pump or blower overloading motor Correct cause of overloading.
Faulty motor Replace motor.
Source
Poor Fire
Flame Detector
Procedure
After burner fires,
immediately jumper across
flame detector terminals at
the primary control.
• If burner continues to
run, this may be due to
poor fire. Inspect fire.
• If fire is good, fault is in
the flame detector.
Check detector circuit.
Causes
Unbalanced fire
Too much air - -lean short fire
Too little air - - long dirty fire
Excessive draft
Too little draft or restriction
Dirty cad cell face
Faulty cad cell - exceeds 15000 hms
Loose or defective cad cell wires
Primary Control olf burner locks out on Primary control circuit defective
safety, fault is in the pri-
mary control.
Correction
Replace nozzle
Reduce combustion air - check
combustion.
Increase combustion air - check
combustion.
Adjust barometric damper for correct draft.
Correct draft or remove restriction.
Clean cad cell face.
Replace cad cell.
Secure connections or replace cad cell
holder and wire leads.
Replace primary control.
Source
Thermostat
Limit Control
Procedure
Check thermostat.
Connect voltmeter between
line voltage connections to
primary control (black &
white leads). If burner
cycles due to power
interruption, it is cycling on
limit.
Causes
Heat anticipator set too low
Vibration at thermostat
Thermostat in the path of a warm air
draft
Dirty furnace air filters
Blower running too slow
Correction
Correct heat anticipator setting.
Correct source of vibration.
Shield thermostat from draft or relocate.
Clean or replace filter.
Increase blower speed to maintain proper
temp. rise.
Check for high static pressure.
Check HEAT selector pin per wiring
diagram (figure 18, page 16).
Blower motor seized or burned out Replace motor.
Blower bearings seized Replace bearings and shaft.
Blower wheel dirty Clean blower wheel.
Blower wheel in backward Reverse blower wheel.
Wrong motor rotation Replace with properly rotating wheel.
Restrictions in return or supply air Correct cause of restriction.
system
Adjustable limit control set too low Reset limit to maximum stop setting.
table continued on next page
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O23V SERIES