Boyertown Cox Heating Products Commercial Furnace - Manual (Page 6)

6
The draft may be accurately
red with any good draft gauge.
ractically all installations. Proper, uniform draft
ator will usually pay for itself in a
ort time through a substantial savings in fuel costs.
ney sizes: Gas
Draft Hood &
Flue Pipe Size
”
320,000………………………….. 8”
……………….. 9”
…….. 10”
……………….. 11”
….. 12”
…………….. 13”
00………………………... 14”
000,001-1,140,000……………………… 15”
If the flue pipe exceeds 10 ft. in length, or
2 elbows use next size larger
.
C.
OIL
D install in rooms with insufficient air to
p
inst
to
ent less
lack flame will be
unit ldings of conventional frame, brick or
win
adeq
r
inst
outs
he outside
twic
each
GPH
the
ng by at least four percent. The
om should be isolated from any area served by
xhaust fans. Do not install an exhaust fan in this
om.
tory combustion is 1 square inch of free area
ously, the
f thermometers, adjust the blower speed
ntil the temperature rise through the unit is equal to
5 degrees – 80 degrees (difference in temperature
etween air entering and leaving the unit).
Unless the temperature of the air entering the units
excessively high (75 degrees or more) such
djustment will result in continued burner operation
ith a high limit setting of 180 degrees to 200
egrees. Should it be impossible to gain an 85
egree temperature rise through the unit, the
dications are that the fan is running too fast for the
en
n
than
ir rcuited back to
In
low thermostat to highest
ti purposes of continued burner operation
stment) and limit control 180 degrees to
not as reliable as that described in the
by the
r
n
high
ation
NOTE: Do not exceed motor rating.
inches at the stack.
measu
Excessive draft causes high stack temperatures and
consequently a waste of fuel. Therefore, a reliable
draft regulator is strongly recommended for
p
insures efficient, economical operation of the burner.
A good draft regul
sh
Minimum recommended chim
Input/hour
Up to 120,000…………………………... 5”
120,001-180,000………………………….. 6
180,001-250,000………………………….. 7”
250,001-
320,001-410,000…………
410,001-510,000……………………
510,001-610,000…………
610,001-730,000………………………
730,001-860,000……………
860,001-1,000,0
1,
NOTE:
contains more than
draft hood pipe and
Combustion Air Supply
o not
sup ly combustion. Occasionally, it is necessary to
all windows or louvers in a door to these rooms,
obtain sufficient air and to prev
atmospheric air pressure in the room. If there is a
of combustion air, the burner
yellow and formation of soot will occur in heating
. In bui
stone construction without utility rooms, basement
dows, or stair doors, infiltration is normally
uate to provide air for combustion and fo
operation of the barometric draft control. For
allation in an enclosed utility room with an
ide wall, a fresh air opening to t
should be made with a free cross sectional area of
e the area of the flue outlet of 100 sq. inches for
gallon nozzle size (Example: 10x10 for 1.00
). For each 1,000 feet above sea level, increase
fresh air openi
ro
e
ro
GAS
Fresh air requirement into the furnace room for
atisfac s
for each 1,000 BTU input and a minimum of 100 sq.
in.
D. Blower Adjustment
Because the Cox Heating unit is so versatile in its
application, it is impossible to be specific in
commending blower speed. Obvi re
quantity and quality of the duct work and the manner
in which it is applied affects the air delivery.
To adjust blower speed to the applied conditions, it
is recommended that the thermostat be set at highest
setting to gain prolonged burner operation. By
eans o m
u
7
b
is
a
w
d
d
in
int
ded application of the furnace. Should the air
bei g supplied to the unit be at a temperature higher
95 degrees, the indications are that the heated
leaving the unit is being short ci a
the unit. The remedy is revision of the supply
system, return system, or both.
many instances, it will be possible to adjust the
er speed by setting the b
set ng (for
during adju
200 degrees, increasing then, the blower speed until
the burner no longer cuts out on high limit. Should
the burner cycle on high limit setting, indications are
that the duct static pressure is higher than intended
by the manufacturer, or the temperature of the air
being supplied the unit is excessive. This latter
method is
foregoing paragraph which will be applied
better qualified installer. Should the blower moto
cut out, indications are: inadequate firing rate, fa
off setting too high, overload of motor, too
temperature air supplied to the unit or a combin
of same. Duct heaters have a minimum air
requirement as given in “Furnace Specification”
Section Chart.