1018454-D
Page 7
NOTE: A preexisting vent that has worked for years may not
be adequate for todays design because of higher efficiency
requirements that result in lower stack temperatures. See
“Possible Causes and Corrective Action” on
pages 30-32
.
NOTE: A partially blocked, inadequate, or disconnected vent
system may not activate the switch.
This appliance must be properly connected to a venting system.
Consult local ordinances governing venting. Install only UL listed type
BW 4” oval gas vent. When the vent enters the attic, a listed type B-1
round flue pipe may be used.
See Figure 7-A (on page 9).
Vent pipe must connect to the wall furnace header plate with a “B” vent
base plate and terminate with a cap at a point at least 12 foot above the
bottom of the wall furnace, two feet above any obstacle within a 10 foot
radius, and at least 3 foot above the roof.
PROVISIONS MUST BE MADE FOR ADEQUATE COMBUSTION
AND VENTILATION AIR.
This appliance is equipped with a manual reset blocked flue switch
designed to protect against a blocked flue condition, which would cause
combustion products to spill back into the living quarters.
Discoloration of the grille is an indication of a bad vent. If this occurs,
the vent can be checked by a qualified serviceman using a draft gauge.
After 15 minutes the gauge should read between -.02 up to -.04 inches
w.c. Vent must be checked at the beginning of each heating season.
Manual Reset Switch
The switch when activated will break the thermostat circuit turning off
the main burner flame. Before the burner will relight, the switch must be
manually reset. See
Figure 4-A (on page 8)
for location of the manual
reset blocked flue switch. To reset the switch, insert a slender rigid
object (i.e. screwdriver) through the front panel louvers and push the
reset button down. See
Figure 4-B (on page 8)
. However, you may
have to remove the front panel, then reset the switch and re-install the
front panel before turning the burner on. If homeowner experiences this
problem, the vent system must be checked and corrected.
All type “B” vents shall extend in a generally vertical direction with
offsets not exceeding 45 degrees, except that a vent system having not
more than one 60 degree offset may be allowed.
Any angle greater than 45 degrees from the vertical is considered
horizontal. The total horizontal run of a vent plus the horizontal vent
connector shall be not greater than 75 percent of the vertical height of
the vent.
Any offsets used should be as far above the drafthood as possible to
allow a venting action to begin before any restriction is encountered.
Based on 4,000 BTU of total input
rating of all gas appliances, the heater
only requires a minimum free area of:
BTU
Square In. Hole Size Square In.
25,000
06.25
1”
0.785
33/35,000
08.75
1.5”
1.760
50,000
12.50
2”
3.140
VENTING
USING ADJACENT
STUD SPACE FOR ALL
COMBUSTION AIR FROM OUTSIDE
Holes Connecting to Ventilated Attic
Holes Connecting to Ventilated Crawl Space
Air
Grille
Floor
Plate
Ceiling
Plate
FIG. 2
