HearthStone Tucson 8702 ST Owner's Manual page 35

Hearthstone Quality Home Heating Products, Inc.
out, if the pilot flame is too small or misdirected away
from the thermopile.
Figure 17: 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 Shutter
The air shutter is used to regulate the air-to-gas
combustion mixture, which in turn influences the size
and color of the flames. The air shutter is 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 shutter may
need adjusting.
To determine if the 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;
AFTER
ALLOWING THE
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2. If the flame is dirty, sooty or licks the top of
the baffle, 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
WARNING: THE ADJUSTING ROD IS HOT!
WARNING: THE AIR SHUTTER IS FACTORY SET
AND ONLY A QUALIFIED GAS TECHNICIAN
SHOULD MAKE ADJUSTMENTS.
The air shutter is adjustable while the stove is
burning. Loosen the set screw on the adjusting rod
located in the lower rear center of the stove. Move
the rod in or out to adjust the flame pattern. See
Photos 36 and 37. Push the rod in to open the air
shutter, and pull it out to close the shutter. When
the flame pattern is correct, tighten the set screw
without letting the rod move.
Photo 36 – Air Shutter Closed
Photo 37 – Air Shutter Opened
Tucson DX/ST Model 8702