15
7061-196J
April 24, 2019
Explorer II
Negative pressure results from the imbalance of air
available for the appliance to operate properly. It can be
strongest in lower levels of the house.
Causes include:
•
Exhaust fans (kitchen, bath, etc.)
•
Range hoods
•
Combustion air requirements for furnaces, water
appliances and other combustion appliances
• Clothes dryers
•
Location of return-air vents to furnace or air
conditioning
•
Imbalances of the HVAC air handling system
•
Upper level air leaks such as:
-
Recessed lighting
-
Attic hatch
-
Duct leaks
To minimize the effects of negative air pressure:
•
Install the outside air kit with the intake facing prevailing
winds during the heating season
•
Ensure adequate outdoor air for all combustion
appliances and exhaust equipment
•
Ensure furnace and air conditioning return vents are
not located in the immediate vicinity of the appliance
•
Avoid installing the appliance near doors, walkways or
small isolated spaces
•
Recessed lighting should be a “sealed can” design
•
Attic hatches weather stripped or sealed
•
Attic mounted duct work and air handler joints and
seams taped or sealed
K. Negative Pressure
J. Clear Space
•
Do NOT place combustible objects within 4 ft (1.2 m) of
the front of appliance
(Figure 15.1)
.
• Mantel:
Avoid placing candles and other heat-sensitive objects
on mantel or hearth. Heat may damage these objects.
Figure 16.1
Maintain 4 ft (1.22m) clearance to
combustible in front of appliance
WARNING
Asphyxiation Risk.
•
Negative pressure can cause spillage
of combustion fumes, soot and carbon
monoxide.
•
Appliance needs to draft properly for
safety.
WARNING
Do NOT place combustible objects in front of the
appliance. High temperatures may ignite clothing,
furniture or draperies.
