HearthStone Bristol DX Owner's Manual page 39

Hearthstone Quality Home Heating Products, Inc.
Symptom Possible Cause
5. Frequent pilot outage A. Pilot flame may be too low or
problem in CPI mode. blowing, (high), causing the pilot
safety to drop out.
B. Excessive draft
6. Glass fogs A. A normal result of gas
combustion in a cold stove.
7. Blue Flames A. A normal result during the first
10 to 20 minutes.
8. Floating flames, lazy ill- A. Potentially dangerous
defined, quiet flames, incomplete combustion due to
which roll around, incorrect air to fuel ratio (lack of
sometimes completely off combustion air or excessive fuel
of the port, sometimes delivery I.e. excessive gas
with overly, yellow tips. pressure, overrating of appliance).
Possible sooting. Usually
accompanied by the odor B. Incorrect air intake/exhaust flow
of aldehydes. system. Causes may be:
B1. Blocked burner.
B2. Blocked primary air
B3. Blocked secondary air inlets
C. Incorrect air shutter position.
9. Burner flashback. Air- A. Excessive primary air.
gas mixture ignites inside
the burner near the orifice, B. Burner input underrated.
usually creating a roaring
noise like a blowtorch. The C. Valve leak if flashback occurs
problem is an imbalance with burner valve in off position.
of gas flow velocity and
burning speed pattern. D. Improper gas pipe size.
10. Delayed ignition A. Incorrect air-to-fuel ratio.
(makes a sudden
"whoosh" noise as the A1. Primary air incorrect.
burner lights). This is a A2. Burner ports plugged.
buildup of gas prior to
ignition. This is more B. Improper log placement.
prevalent with propane
(LP) fuel. C. Pilot shield not installed
properly.
11. Surface fissures form A. Normal occurrence during the
in ceramic burner surface. first few hours of operation.
Corrective Action
A. Clean and/or adjust the pilot flame for maximum
impingement on the rectification sensor.
B. Check Restriction settings per this manual.
A1. After the heater has warmed up, the glass should clear.
A2. Leave pilot in CPI mode to keep stove warmer.
A. Flames should begin to turn more yellowish after 20
minutes of burning.
B. If the blue color stays; adjust the air shutter for a proper
burn.
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(s) for a proper burn.
A. Adjust the air shutter(s) 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.
A1. Adjust the air shutter for a proper burn.
A2. Open ports to allow for proper travel of flames.
B. Reposition logs to eliminate interference with flame travel.
C. Ensure the pilot shield is installed in the proper position (if
present).
A. None. Fissures may form at the first firing – then remain
stable for the life of the burner.
39
Bristol Model 8762