30
SYMPTOMS
POSSIBLE CAUSE(S)
CORRECTIVE ACTION
Table 8A – Tubular Duct Furnace Troubleshooting Guide
A. Flame pops back.
B. Noisy
fl
ame.
C. Yellow tip fl ame.
Note: Some yellow tipping
on LP gas is permissible.
D. Floating
fl
ame.
E. Gas
odor.
Shut off gas supply
immediately!
F. Delayed
ignition.
1. Burner orifi ce too small.
1. Irregular orifi ce causing whistle
or
resonance.
2. Excessive gas input.
1. Clogged main burners.
2. Misaligned
orifi
ces.
3. Insuffi cient combustion air.
4. Unit possibly over fi red.
5. Partially blocked fl ue vent pipe.
1. Blocked
venting.
2. Insuffi cient combustion air.
3. Blocked heat exchanger.
4. Air leak into combustion chamber or
fl
ue
collector.
1. Gas
leak.
Shut off gas supply
immediately!
2. Leaking gas test port on valve.
3. Blocked heat exchanger.
4. Blocked fl ue collector.
5. Negative pressure in the building.
1. Improper
ground.
2. Bad or broken spark cable.
3. Faulty control board.
4. Pressure regulator set too low.
5. Main burner orifi ces dirty.
6. Improper
venting.
1. Check with local gas supplier for proper
orifi ce size and replace. Refer to “Gas
Input Rate” section of this manual.
1. Replace
orifi
ce.
2. Test and reset manifold pressure (see
“Gas Supply Pressure” Table in
the Pipe Installation section of this
manual.)
1. Clean main burner ports.
2. Replace manifold assembly.
3. Refer to “Installation - Clearances”
and “Venting” sections in this manual
to ensure unit is properly mounted
and
vented.
4. Check gas input and manifold
pressures.
5. Check fl ue vent pipe and clear as
needed.
1. Check fl ue vent pipe and clear as
needed.
2. Check combustion air inlet openings
and/or vent pipe and clear as needed.
3. Clean heat exchanger. Refer to
“Maintenance” section of this manual.
4. Check fl ue collector and clear as
needed.
1. Inspect all gas piping and repair
accordingly.
2. Check to ensure gas test ports are
sealed.
3. Clean heat exchanger. Refer to
“Maintenance” section of this manual.
4. Check fl ue collector and clear as
needed.
5. See “Installation” section of this
manual.
1. Check grounding wires and spark
ignitor
connections.
2. Inspect spark cable connections and
cuts. Replace if necessary.
3. Check to ensure spark ignitor is
energized after pre-purge period.
4. Test and reset manifold pressure (see
“Gas Supply Pressure” Table in
the Pipe Installation section of this
manual.)
5. Clean or replace orifi ces.
6. Refer to “Venting” section of this
manual.
