SYMPTOMS
POSSIBLE CAUSES
CHECK/REMEDIES
14. Soot in heat exchanger
Improper fuel/air mixture Check and adjust gas pressure
Check for proper burner orifices
Improper LP conversion
Insufficient combustion air Check for proper combustion air
and vent piping
Check for recirculation of
combustion gases
15. System starts, cycles four
times and locks out
Low gas pressure Measure gas pressure;
correct if necessary
Gas valve(s) set to off position
Insure all gas valves open
Reversed polarity of main power Reverse power leads in unit "J" box
Damaged igniter Replace igniter
Damaged igniter/flame sensor wiring Check wiring harness for breaks
or loose connections
Moisture in junction plug
Check for moisture in plug
connections
Improper unit grounding Check wiring, insure properly
grounded unit
Restricted combustion air or vent pipe Correct as necessary
Damaged integrated furnace
control board
Test and replace if necessary
Damaged flame sensor Check and replace if necessary
16.
Blower (only) operates
continuously
Thermostat fan switch set
to the "ON" position
Set fan switch to the
"AUTO'' position
Malfunctioning integrated
furnace control board
Test and replace IFC
if necessary
17. Induced draft blower and main
blower operate continuously
Open limit or overtemperature switch;
open wire or loose junction plug
Check and correct as necessary
18. Induced draft blower pulsates
on and off
Incompatible thermostat
Add isolation relay
Replace thermostat
19.
Pressure switch fails to close Leaking induced draft blower gasket Replace with new gasket
Blocked or restricted vent or
combustion air pipe
Check for improper pipe length,
number of elbows, or blockage
Damaged heat exchanger Replace heat exchanger
Condensate does not drain Remove blockage
Insure proper condensate vent
Condensate trap dry Fill trap with water
20. Water leakage
Drain trap not properly sealed Seal according to instructions
Drain pipe leaks
Repair as needed
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