Furnace - Electronic Ignition Models - Atwood AFS Series Training Manual

BURNER FAILS TO IGNITE AND - BLOWER FAILS TO RUN
No electrical power to the furnace
Thermostat defective
Thermostat wires broken or shorted
Current overload protector device
Defective or tripped (circuit breaker)
Furnace – Electronic Ignition Models
* NOT COVERED UNDER WARRANTY
CAUSE
Blower relay defective
Wire off motor
Wire off relay
Improper ground
Blower motor defective
BLOWER RUNS – BUT FAILS TO IGNITE
Low voltage/High voltage
Gas pressure incorrect
Furnace grounding wires not secure
Air intake restricted
Motor running slow
12 volt polarity reversed
Exhaust blocked
Combustion air wheel loose
Sail switch defective or wire off
Limit switch defective or wire off
Edge connector or circuit board dirty
Circuit Board defective
Gas valve defective
Main burner orifice blocked
High tension lead wire defective
Electrode out of adjustment
Electrode defective
Obstructed burner head
BURNER IGNITES BUT IGNITION SYSTEM "LOCKS OUT" AND TURNS BURNER OFF
Low gas pressure
Exhaust blocked
Combustion air wheel loose
Electrodes out of adjustment
Electrode defective
Circuit Board defective
Flame sensor wire between electrode and circuit board
defective
Air leakage at gaskets
Defective heat exchanger
SOOT (caused by lazy yellow flame)
Low gas pressure
Low voltage
Air leakage at gaskets
Combustion wheel installed backwards or loose
Blockage in heating chamber or burner head
Faulty motor
Wrong vent kit or draft cap
FAN RUNS CONTINUOUSLY WITH THERMOSTAT "OFF"
Defective thermostat
Shorted thermostat leads
Defective relay
LIMITING = BURNER CYCLING ON AND OFF – BLOWER RUNS CONSTANTLY WITH THERMOSTAT ON
Reconnect or replace power source. *
Replace thermostat
Replace wire or wires *
Reset circuit breaker. Check amp draw from motor
According to furnace specifications
Replace relay
Reconnect wire
Reconnect wire
Clean and secure grounds *
Replace motor
Correct power supply *
Set pressure to a minimum of 11" W.C. with all appliances running. (Replace
regulator if not obtainable) *
Clean and secure grounds established *
Clean air intake *
Check voltage first. If 12 VDC while running, replace motor
Correct polarity *
Clean exhaust *
Reposition and tighten
Reconnect wire or replace
Reconnect wire or replace
Clean with pencil eraser *
Clean plug contacts. If still defective, replace. (check on board tester when
possible)
Replace valve or valve coil, depending on problem encountered
Clean main burner orifice or replace.
Replace wire
Adjust electrode (take care not to damage porcelain)
Replace
Clean burner head *
Set pressure to a minimum of 11" W.C. with all appliances running Replace
regulator if not obtainable *
Clean exhaust *
Reposition wheel and tighten
Adjust electrode according to furnace specifications
Replace electrode
Clean plug contacts. If still defective, replace (Check on board tester when
possible)
Replace wire
Replace gasket
Replace heat exchanger
Set pressure to a minimum of 11" W.C. with all appliances running. Replace
regulator if not obtainable *
Correct power supply *
Replace gaskets
Reposition wheel and tighten
Clean or replace
Replace motor
Replace with correct vent kit or draft cap
Replace thermostat
Replace wire or wires *
Replace relay
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SOLUTION