HearthStone 8762 User Manual page 31

Hearthstone Quality Home Heating Products, Inc.
Figure 29 - Pilot Flame Pattern
WARNING: THE CONTROL HAS AN INTERLOCK
DEVICE. IF THE STOVE HAS BEEN LIT, IT WILL
NOT RELIGHT AGAIN IMMEDIATELY.
SHUTTING OFF ALL GAS FLOW, THE PILOT
BURNER CANNOT BE RELIT UNTIL THE FLAME
SENSOR HAS COOLED,
ELECTROMAGNET TO BE RELEASED (APPROX.
60 SEC.).
Air Shutters
The air shutters are used to regulate the air-to-gas
combustion mixture of each burner, which in turn
influences the size and color of the flames. The air
shutters are factory positioned in the general
location needed for testing the unit with natural gas
(NG) and minimum venting. However, if the unit is
not burning as well as it should in your installation,
then the air shutters may need adjusting.
To determine if an air shutter needs adjustment, it is
necessary to view the flame pattern with the burner
output set at its highest setting. Allow the unit to
operate for at least 10 minutes to allow the entire
unit to reach temperature, and for the flame pattern
to stabilize. Generally, the more air (open shutter) in
the mixture, the bluer the flame. Less air (closed
shutter) results in a more yellow flame, but too little
air will result in incomplete combustion, low
efficiency and a dirty burn. There are two simple
guidelines to aid in determining the correct flame
pattern:
1. If the flame just above the surface of the
burner or at the base of the logs is
completely blue, the air shutter may be open
too far;
2. If the flame is dirty, sooty, or licks the top of
the firebox, the air shutter may be closed too
far.
Some conditions cannot be corrected through air
shutter adjustment; an adjustment must be made to
the gas supply pressure or by changing the
restriction plate setting. Qualified service personnel
must perform supply line/manifold gas line pressure
adjustments and restrictor plate adjustments. Do not
attempt to complete any part of the installation or
adjustment of this unit unless technically qualified.
Air Shutter Adjustments
The air shutters are adjustable while the stove is
burning. Loosen the set nut of the specific shutter
that needs adjustment (located on the bottom of the
stove). Move the shutter left or right to adjust the
flame pattern. See Figures 30 and 31. Move the
AFTER
shutter towards the valve to open the air shutter, and
away to close the shutter. When the flame pattern is
correct, tighten the set nut without letting the shutter
ALLOWING THE
move.
31
WARNING: THE ADJUSTING STUDS ARE HOT!
WARNING: THE AIR SHUTTERS ARE FACTORY
SET AND ONLY A QUALIFIED GAS TECHNICIAN
SHOULD MAKE ADJUSTMENTS.
Figure 30 - Air Shutters Closed
Figure 31 - Air Shutters Opened
Bristol Model 8762