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1,000 Btu/ft
3
is determined by-
Corrected Input = 90,000 - (6,000 X .04) X (90,000 / 1,000)
Corrected Input = 90,000 - (240 X 90)
Corrected Input = 90,000 - 21,600
Corrected Input = 68,400
Using the orifices sized as shown in the table for 6,000 feet (#45),
a meter time of 52.6 seconds is measured. The actual firing rate
of the furnace is
Input = 1,000 (heating value of the gas) X 3600 (constant) / 52.6
(meter time for 1 ft
3
of gas)
Input = 3,600,000 / 52.6
Input = 68,400 Btu/h
M
T
I
M
ETER
IME
N
INUTES AND
R
F
E
ATING OF
URNACES
G
A
0 - 2,000 F
AS
T
INPUT
METER
HEAT
SIZE
VALUE
3
Btu/hr
900
FT
MIN. SEC.
40,000
1
1
10
13
60,000
1
0
10
9
80,000
1
0
10
6
100,000
1
0
10
5
120,000
1
0
10
4
In Canada, the series and rating plate input for the furnace apply
to installations up to 2,000 feet (610m) above sea level. Kit HA-02
for natural and LP gases is required to convert furnaces from
elevations of 2,000 to 4,500 feet (610m to 1,370m). Canadian
certification applies to the installations of up to 4,500 feet above
sea level. Installations above 4,500 feet are subject to acceptance
by the local authorities having jurisdiction.
Do not derate the furnace by adjusting the manifold pressure to a
lower pressure than specified on the furnace rating plate. The
combination of the lower air density and a lower manifold pressure
will prohibit the burner orifice from drawing the proper amount of
air into the burner. This may cause incomplete combustion,
flashback, and possible yellow tipping.
In some areas the gas supplier may artificially derate the gas in an
effort to compensate for the effects of altitude. If the gas is artificially
derated, the appropriate orifice size must be determined based
3
upon the BTU/ft
content of the derated gas and the altitude. Refer
to the National Fuel Gas Code, NFPA 54/ANSI Z223.1, and
information provided by the gas supplier to determine the proper
orifice size.
A different pressure switch may be required at high altitude
regardless of the BTU/ft
3
content of the fuel used. Contact your
distributor for a tabular listing of appropriate altitude ranges and
corresponding manufacturer's pressure switch kits.
P
G
C
ROPANE
AS
ONVERSION
IO-247A
S
F
N
ECONDS
OR
ORMAL
F
U
W
N
QUIPPED
OR
SE
ITH
A
EET
LTITUDE
HEAT
HEAT
VALUE
VALUE
1,000
1040
MIN.SEC
MIN. SEC.
21
1
30
1
33
30
15
00
15
36
16
54
1
00
1
03
00
10
10
10
24
41
0
45
0
47
45
7
30
7
48
32
0
36
0
37
24
6
00
6
14
27
0
30
0
31
30
5
00
5
12
P
OSSIBLE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH MAY OCCUR IF
THE CORRECT CONVERSION KITS ARE NOT INSTALLED.
MUST BE APPLIED TO INSURE SAFE AND PROPER FURNACE OPERATION.
CONVERSIONS MUST BE PERFORMED BY A QUALIFIED INSTALLER OR SERVICE
AGENCY.
This unit is configured for natural gas. The appropriate
manufacturer's propane gas conversion kit, must be applied for
propane gas installations. Refer to the "Propane Gas and/or
High Altitude Installations" section for details.
Contact your distributor for a tabular listing of appropriate
manufacturer's kits for propane gas and/or high altitude installations.
I
NPUT
The indicated kits must be used to insure safe and proper furnace
operation. All conversions must be performed by a qualified
ATURAL
installer, or service agency.
G
P
C
AS
IPING
HEAT
VALUE
G
ENERAL
1,100
MIN. SEC.
1
39
30
T
O AVOID POSSIBLE UNSATISFACTORY OPERATION OR EQUIPMENT DAMAGE
1
06
DUE TO UNDERFIRING OF EQUIPMENT, USE THE PROPER SIZE OF
11
00
NATURAL/PROPANE GAS PIPING NEEDED WHEN RUNNING PIPE FROM THE
0
50
METER/TANK TO THE FURNACE.
8
15
0
40
When sizing a trunk line, be sure to include all appliances which
6
36
will operate simultaneously when sizing a trunk line.
0
33
The gas piping supplying the furnace must be properly sized based
5
30
on the gas flow required, specific gravity of the gas, and length of
the run. The gas line installation must comply with local codes, or
in their absence, with the latest edition of the National Fuel Gas
Code, NFPA 54/ANSI Z223.1.
Length of
Pipe in Feet
10
20
30
40
50
60
70
80
90
100
(Pressure 0.5 psig or less and pressure drop of 0.3" W.C.; Based on
0.60 Specific Gravity Gas)
CFH = BTUH Furnace Input
Heating Value of Gas (BTU/Cubic Foot)
To connect the furnace to the building's gas piping, the installer
must supply a ground joint union, drip leg, manual shutoff valve,
and line and fittings to connect to gas valve. In some cases, the
installer may also need to supply a transition piece from 1/2" pipe
to a larger pipe size.
The following stipulations apply when connecting gas piping. Refer
to Figure 16 for typical gas line connections to the furnace.
• Use black iron or steel pipe and fittings for the building piping.
• Use pipe joint compound on male threads only. Pipe joint
compound must be resistant to the action of the fuel used.
• Use ground joint unions.
18
WARNING
ONNECTIONS
CAUTION
Natural Gas Capacity of Pipe
In Cubic Feet of Gas Per Hour (CFH)
Nominal Black Pipe Size
1/2"
3/4"
1"
132
278
520
92
190
350
73
152
285
63
130
245
56
115
215
50
105
195
46
96
180
43
90
170
40
84
160
38
79
150
T
HE APPROPRIATE KITS
A
LL
1 1/4"
1 1/2"
1050
1600
730
1100
590
980
500
760
440
670
400
610
370
560
350
530
320
490
305
460
12/04
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