Lennox Hearth Products EARTHSTOVE 1400HT, Installation And Operation Manual

INSTALLATION 

PAGE 10 

DRAFT REQUIREMENTS 

The appliance is merely one component of a larger sys-
tem. The other equally important component is the vent-
ing system which is necessary for achieving the re-
quired flow of combustion air to the fire chamber and for 
safely removing unwanted combustion byproducts from 
the appliance. If the venting system's design does not 
promote these ends, the system may not function prop-
erly. Poorly functioning venting systems may create 
performance problems (i.e. smoking stove, poor heat 
output, fire goes out, window blackens, increased creo-
sote buildup, etc.) as well as be a safety hazard. Some 
factors that may lead to performance problems are as 
follows: 
 

• 

Oversized or undersized chimney. 

• 

Excessive offsets in venting. 

• 

Insufficient vertical height of chimney. 

• 

Insufficient chimney termination height in relation-
ship to roof. 

• 

Insufficient ventilation. 

• 

Lack of maintenance. 

• 

Improper operation. 

• 

Burning improper fuel (unit is approved for use with 
natural dry well-seasoned wood only). 

• 

Down drafts in the chimney (may need a special wind 
cap). 

 
To ensure that the venting system is functioning prop-
erly a draft test should be performed (see 

Draft Test 

Procedure

 on this page). 

American National Standards Institute ANSI/NFPA 211-
92: A chimney or vent shall be so designed and con-
structed to develop a flow sufficient to completely re-
move all flue and vent gases to the outside atmosphere. 
The venting system shall satisfy the draft requirements 
of the connected appliance in accordance with the 
manufacturer instructions. 

DRAFT TEST PROCEDURE 

After this appliance is installed a draft test should be 
performed to ensure proper draft. A qualified technician 
should perform the draft test procedure as follows: 
 
1)  Close all windows and doors in the dwelling. 
2)  Turn on or operate all appliances which remove air 

from the home (such as a furnace, heat pump, air 
conditioner, clothes dryer, exhaust fans, fireplaces, 
and other fuel burning appliances). 

3)  Drill a hole in the vent pipe per the draft gauge 

manufacturers instructions (to create a draft test 
port). Note: Hole location should be a minimum of 1 
foot above flue outlet collar. 

4) Start a fire (See 

How To Start And Maintain A Fire

on page 16). 

5)  After the fire is well established (20-25 minutes) 

and burning at a low setting, perform the draft test 
per the gauge manufacturer instructions. The draft 
gauge should read between .05 and .07” W.C. (inches 
water column). Excessive draft (above .07 W.C.I.) can 
result in too much combustion air to be pulled into the 
firebox, this will produce hotter burns and could result in 
overfiring. Too little draft (below .05” W.C.) will not allow 
enough combustion air delivery to maintain a fire well or 
cause performance problems such as smoking (this 
may result in improper operation of appliance, i.e. will 
not maintain fire well unless fuel door is left open). 

6)  Install a screw to seal the draft test port in the vent pipe. 

If the draft test reading was not within the required 
range, correct the installation and repeat this proce-
dure. 

 
VENTILATION REQUIREMENTS / PROVIDE ADE-
QUATE AIR FOR COMBUSTION  
 
THE FRESH AIR REQUIREMENTS OF THIS APPLI-
ANCE MUST BE MET WITHIN THE SPACE WHERE 
IT WILL BE INSTALLED. VENTILATION IS ESSEN-
TIAL WHEN USING A SOLID FUEL BURNING 
HEATER.

 
In well insulated and weather tight homes, it may be 
difficult to establish a good draft up the chimney 
(caused by a shortage of air in the home). The lack of 
air is caused by many common household appliances 
which exhaust air from the home (such as a furnace, 
heat pump, air conditioner, clothes dryer, exhaust fans, 
fireplaces, and other fuel burning appliances). Also, the 
combustion process of this heater uses oxygen from 
inside the dwelling.  If the available fresh air delivery in 
the dwelling is insufficient to support the demands of 
these appliances, problems can result (i.e. excessive 
negative pressure can develop in the dwelling which will 
affect the rate at which this appliance can draft thus 
resulting in performance problems; See 

Draft Require-

ments

 on this page). To correct this problem it may help 

to open a window (preferably on the windward side of 
the house) or install a vent to provide make-up air into 
the dwelling.