HearthStone STERLING "G" B-VENT 8521, Owner'S Manual

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Home 

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Inc. 

                  ODEL 

8521 

Sterling 

“G” 

B-Vent 

14 

Initial adjustments 

Variable Output Control  

The gas control valve is equipped with a variable 

output control.  This control varies the

rate

of heat 

produced by the unit by varying the gas pressure to 

the main burner tube.  The 

length

of the burn cycle 

is affected by a combination of heat output and the 

thermostat setting.  If your stove cycles 

OFF & ON

often, try reducing the burn with the gas control 

valve first.   
 
Using the variable output control, the heat output of 
the unit can be reduced for mild Fall and Spring 
months or maximized for the colder Winter months.  
This adjustment can be made by the homeowner as 
necessary by turning the variable output control 
knob to 

HI or LO

 or any setting in between. 

Air Shutter Adjustments  

The air shutters are preset by the manufacturer 

for optimum operation and should not need 

adjustment by the owner.

  There are adjustable air 

shutters located on the main burner tubes on the 

right rear of the unit behind the right rear cover.  The 

air shutters are used to regulate the air-to-gas 

combustion mixture which in turn influences the size 

and color of the flames.  However, it may need 

adjustment once the unit has been installed to 

compensate for variations in supply line pressure, 

altitude and other variables. 

To determine if the air shutters need adjustment, it is 

necessary to view the flame pattern with the variable 

output control knob at its highest setting.  Allow the 

unit to operate for 10 minutes to allow the entire unit 

to reach temperature and for the flame pattern to 

stabilize.  

There are two simple guidelines to aid in 

determining the correct flame pattern:  1) If the flame 

at the base of the logs is completely blue, the air 

shutters may be open too far;  2) If the flame is dirty 

or licks the top of the stove, the air shutters may be 

closed too far. 

To adjust the air shutter openings, simply loosen 

the screw on the shutter, clamp and pull the 

adjustment rod to close the air opening, or push the 

adjustment rod to open the air opening.  Closing the 

air shutters allow less oxygen to burn and results in 

a higher, yellow flame.  Opening the shutters allow 

more oxygen to burn and results in a lower, blue 

flame.  Adjustment may be done while viewing the 

fire.  Once the desired flame pattern is achieved, 

tighten the screw. 

WHEN TIGHTENING THE

SHUTTER CLAMP 

SCREW, DO NOT OVER-TIGHTEN. TIGHTEN 

UNTIL THE SCREW-HEAD TOUCHES METAL, AND 

THEN ANOTHER 1/4 TURN.

Supply line and manifold gas pressure 

adjustments must be performed by 

qualified 

service personnel

.

  Do not attempt to complete any 

part of the installation or adjustment of this unit 

unless technically qualified to do so. 

When adjusting the air shutters for flame color 

take care not to obtain a flame which is too yellow 

(shutters closed; too little oxygen).  While such a 

flame may be aesthetically pleasing, it is the result of 

incomplete combustion which will eventually result in 

an accumulation of carbon in the firebox, on the 

logs, burner tubes and window glass. 

LOCATED BEHIND REAR PANEL

Sterling BV 

Rear View

SHUTTER ADJUSTMENT RODS 

SETTING

LP

SETTING

NG

SHUTTER CLAMP

NG

SETTING

LP

SETTING

FRONT BURNER TUBE
SHUTTER  ADJUSTMENT ROD

SHUTTER CLAMP SCREW

REAR BURNER TUBE
SHUTTER  ADJUSTMENT ROD

Sterling BV Air 

Shutter Adjustment

FIREBOX

FOR CLARITY

GAS LINES NOT SHOWN 

SLIDE

SLIDE

Sterling BV Flame Pattern