SYMPTOM
CAUSE
REMEDY
Loud, high-pitched
whine
Flame is too rich.
Verify pressure tap between gas valve and
blower inlet.
Verify that the gas regulator setting is 11 ±
5 Pa.
Contact a qualified technician or service
agency to replace the gas orifice.
Flame is “fluttery .”
Exhaust may have acrid
smell or burner may fail
to stay lit.
Flame is too lean.
Verify that the gas regulator setting is 11 ±
5 Pa.
Contact a qualified technician or service
agency to replace the gas orifice.
Combustion appears
normal, but flame does
not stay lit.
Flame current is not
being sensed.
Check for wet or damaged igniter with low
resistance to ground. Replacewith new
igniter.
Verify burner flameholder is properly
grounded.
Replace Ignition Control Module.
SYMPTOM
CAUSE
REMEDY
Boiling in heat
exchanger. May be
accompanied by
“bumping” sounds.
Low water flow to
heater.
Heat exchanger
plugged.
Bypass valve stuck
open.
Thermal governor
stuck closed.
Service pump and or filter.
Service heat exchanger. Correct water
chemistry.
Service bypass valve.
Replacethermal governor.
Sweating.
Thermal governor
failed.
Replacethermal governor.
Heat Exchanger Troubleshooting
Burner Troubleshooting