HearthStone Quality Home Heating Products, Inc.
MODENA 8140 Gas-Fired Direct-Vent
25
Troubleshooting
Symptom
Possible Cause
Corrective Action
8. Floating flames, lazy
ill-defined, quiet flames,
which roll around,
sometimes completely
off 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).
B. Incorrect air intake/exhaust flow
system. Causes may be:
B1. Blocked burner.
B2. Blocked primary air
B3. Blocked secondary air inlets
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.
B1. Clear ports.
B2. Clear obstructions.
B3. Clear obstructions.
C. 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 primary air.
B. Burner input underrated.
C. Valve leak if flashback occurs
with burner valve in off position.
D. Improper gas pipe size.
A. Adjust the air shutter for a proper burn.
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. Replace valve. If above corrections do not eliminate
flashback, replace burner.
D. Correct plumbing.
10. Delayed ignition
(makes a sudden
"whoosh" noise as the
burner lights). This is a
buildup of gas prior to
ignition. This is more
prevalent with propane
(LP) fuel.
A. Incorrect air-to-fuel ratio.
A1. Primary air incorrect.
A2. Burner ports plugged.
B. Improper stone placement.
A1. Adjust the air shutter for a proper burn.
A2. Open ports to allow for proper travel of flames.
B. Reposition stones to eliminate interference with
flame travel.
