HearthStone Quality Home Heating Products Inc
STOWE Gas-Fired Direct Vent heater
37
TROUBLESHOOTING (cont.)
Symptom
Possible Cause
Corrective Action
8. Floating flames,
lazy ill-defined,
quiet flames that
roll around,
sometimes
completely off of
the port,
sometimes with
overly yellow tips.
Possible sooting.
Usually
accompanied by
the odor of
aldehydes.
A. Potentially dangerous
incomplete combustion due
to incorrect air to fuel ratio
(lack of combustion air or
excessive fuel delivery I.e.
excessive gas pressure,
overrating of appliance).
A. Check the appliance input rate and reduce
if necessary. The air intake/exhaust flow
system may be too restrictive or blocked (the
rate at which the exhaust leaves [draft]
determines the rate at which the combustion
air is delivered). Poor draft results in
insufficient air delivery or a restricted
exhaust. Correct air intake/exhaust flow
system.
B. Incorrect air
intake/exhaust flow system.
Causes may be:
B1. Blocked Burner.
B2. Blocked primary air.
B3 Blocked secondary air
inlets.
B1. Clear ports.
B2. Clear obstructions.
B3. Clear obstructions.
Note: If gas pressures are correct and the
flames stay the same, adjust the air shutter
for a proper burn.
9. Burner
flashback. Air-gas
mixture ignites
inside the burner
near the orifice,
usually creating a
roaring noise like a
blowtorch. The
problem is an
imbalance of gas
flow velocity and
burning speed
pattern.
A. Excessive draft.
A. Adjust the air shutter for a proper burn.
B. Burner input underrated. B. Check input rate. Check input pressure
using a manometer. Confirm correct gas
pressure at house meter or tank (call gas
company). Confirm burner orifice size.
C. Valve leak if flashback
occurs with burner valve in
off position
C. Replace valve. If above corrections do not
eliminate flashback, replace burner.
D. Improper gas pipe size.
D. Correct plumbing.
