Harman SF 250, Installation And Operating Manual

7

ChImNEY & vENTINg

Possible causes of insufficient draft;

A. Chimney Leaks - Air leaking in around a loose fit

-

ting cleanout door, flue pipe joints and/or seams not 

secured, improper plug openings or defective ma

-

sonry.

B. Chimney Too Short - The general rule for chimneys; 

16 feet tall, three feet above the roof exit, and two feet 

taller than anything within ten feet.

C. Blocked Chimney

 - Have the chimney cleaned and 

inspected prior to installation and before each heating 

season. 

D. Trees Or Other Topographical Barriers - Impeding 

on the chimney’s operation or causing a down draft 

situation. This can also be caused by adjacent build

-

ings or another roof of the same structure giving air 

currents a downward swirl.

NOTE: The chimney on the illustrated house is too 

low, it should be raised to compensate for down draft 

potential.

E. Chimney Size - The chimney can not be smaller 

than the flue exit from the appliance. Too large of a 

chimney could stay too cool to promote adequate 

draft.

F. Chimney Offsets - Offset chimneys should be 

avoided. The offset area can collect debris and cause 

a blockage.

G. Elbow restrictions

 - There should be no more than 

two 90° elbows or the equivalent used in connecting 

the stove to the chimney flue.

H. Shared Flue - No more than one appliance shall 

vent into a single flue.

The most common cause of poor draft is an improp-

erly sized flue liner. It is recommended that the inside 

Wind direction

dimensions of the liner be at least as large as the ap-

pliance flue outlet and no larger than 125% of the col

-

lar for a round flue. An example, a 8” flue collar is 50 

square inches. Increased by 25% would be 63 square 

inches, or approximately a 9” round flue. In general 

for round liners, it is recommended that they not be 

increased by more than one inch from that of the stove 

collar. This will help ensure proper draft with the lower 

flue temperatures. 

REMEMBER; 

A solid fuel burning stove can only per-

form as well as its venting system will allow it to.

THE MOST IMPORTANT THING TO REMEMBER 

ABOUT CHIMNEYS IS THEIR NEED FOR MAIN-

TENANCE AND CLEANING. IF A CHIMNEY IS NOT 

CLEANED ON A FREQUENT BASIS, IT WILL AF

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FECT THE DRAFT AS WELL AS BEING A CONTRIB-

UTING CAUSE TO A POSSIBLE CHIMNEY FIRE.

IF YOu hAvE A ChImNEY FIrE:

. GET EVERYONE OUT OF THE HOUSE.
. CALL THE FIRE DEPARTMENT.
3. CLOSE THE DRAFT CONTROL KNOBS ON THE 

STOVE.

DO NOT USE THE CHIMNEY UNTIL IT HAS BEEN 

THOROUGHLY CLEANED AND INSPECTED BY A 

QUALIFIED PERSON.