John Wood Commercial - ANED - Manual (Page 6)

INPUT
BTU/HR.
58,000
90,000
135,000
160,000
180,000
200,000
225,000
270,000
315,000
360,000
NATURAL GAS
1000 BTU/CU. FT.
62 SEC.
40 SEC.
27 SEC.
22 SEC.
20 SEC.
18 SEC.
16 SEC.
13 SEC.
12 SEC.
10 SEC.
PROPANE
2500 BTU/CU. FT.
155 SEC.
100 SEC.
67 SEC.
56 SEC.
50 SEC.
45 SEC.
40 SEC.
33 SEC.
29 SEC.
25 SEC.
Table II
No. of seconds required to consume 1 cu. ft. of gas.
VENTING
To carry off the products of combustion, a vent pipe must be
attached to the drafthood of the heater and connected to a
chimney vent of adequate height and area. Venting
connections should be made in accordance with all codes
and ordinances which apply.
Ensure that the vent pipe is securely fastened to the draft hood
and that the draft hood is properly attached to the heater. For a
single heater installation the vent pipe must be sized no small-
er than the flue size of the heater. Horizontal runs of vent pipe
should be installed with a rise of at least 1/4” per foot of length.
The vertical connector rise of vent pipe above the draft hood,
before any fittings, should be as great as possible.
When more then one heater is installed and the vents are
combined, the area of the horizontal manifold and common
vent should be at least equal to the area of the largest single
vent, plus 50% of the area of all other vents joining it (see
Vent Size Chart below) (For example, to combine two 6” vents
with a 5” vent, the area of the combined vent would be equal
to 28 + 28/2+20/2 equals 52 square inches - use a minimum
9 inch common vent and manifold). Units with larger inputs
must be vented below others. When using a common vent
connector, it shall be at the highest practical level.
The chimney vent must be extended at least two feet higher
than any obstruction located within 10 feet.
Where a back draft exists, the cause must be determined and
corrected. A flue cap on the chimney vent may correct the sit-
uation. However, if the back draft cannot be corrected, if long
horizontal vent pipe runs are necessary, or if a suitable flue
cannot be obtained, a mechanical exhaust may be required to
ensure proper venting and combustion.
Some local codes prohibit connecting a gas heater to a flue or
chimney with coal or oil fired equipment. Therefore, these
connections should be avoided. However, where a separate
chimney is not available, the flue pipe from the water heater
should enter the common flue or chimney at a point ABOVE
the flue pipe from the coal or oil fired equipment.
Improper venting may result in poor combustion, sooting and
serious damage to the heater.
DIA.
IN.
5
6
7
8
9
AREA
SQ. IN.
20
28
38
50
64
DIA.
IN.
10
12
14
16
AREA
SQ. IN.
79
113
154
201
VENT TOP
OR CAP
COMMON
CHIMNEY VENT
MANIFOLD
CONNECTOR
RISE
VENT
CONNECTOR
TEE
CAPPED
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