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GAS PIPING
To avoid damage or possible personal injury, do not connect gas piping to this unit
until a supply line pressure/leak test has been completed. Connecting the unit before completing the
pressure/leak test may damage the unit gas valve and result in a fi re hazard.
Do not rely on a shut-off valve to isolate the unit while conducting gas pressure/leak
tests. These valves may not be completely shut off, exposing the gas valve to excessive pressure and
damage.
NOTICE: If more than one unit heater is to be served
by the same piping arrangement, the total cu. ft./hr.
input and length of pipe must be considered.
NOTICE: If the gas unit heater is to be fi red with LP
gas, consult your local LP gas dealer for pipe size
information.
NOTICE: HEATER INSTALLATION FOR USE WITH
PROPANE (BOTTLED) GAS MUST BE MADE BY
A QUALIFIED L.P. GAS DEALER OR INSTALLER.
HE/SHE WILL INSURE THAT PROPER JOINT
COMPOUNDS ARE USED FOR MAKING PIPE
CONNECTIONS; THAT AIR IS PURGED FROM
LINES; THAT A THOROUGH TEST IS MADE FOR
LEAKS BEFORE OPERATING THE HEATER; AND
THAT IT IS PROPERLY CONNECTED TO THE
PROPANE GAS SUPPLY SYSTEM.
Before any connection is made to the existing line
supplying other gas appliances, contact the local gas
company to make sure that the existing line is of adequate
size to handle the combined load.
1. Determine the required Cu. Ft./Hr. by dividing the input by 1000. For SI/Metric measurements: Convert BTU/Hr. to kilowatts. Multiply the units
inputs (kW) by 0.0965 to determine Cu. Meters./Hr. 2. FOR NATURAL GAS: Select pipe size directly from the table. 3. FOR PROPANE GAS:
Multiply the Cu. Ft./Hr. value by 0.633; then, use the table. 4. Refer to the metric conversion factors listed in the General Safety section for SI Unit
measurement conversions.
Maximum Capacity of Pipe in Cubic Feet of Gas per Hour (Cubic Meters per Hour) for Gas Pressures of 0.5 psig (3.5 kPa) or Less,
and a Pressure Drop of 0.5 Inch Water Column (124.4 Pa)
(Based on a 0.60 Specifi c Gravity Gas)
Nominal
Iron Internal Length of Pipe, Feet (meters)
Pipe Size
Dia. 10 20 30 40 50 60 70 80 90 100 125 150 175 200
in. in. (3.0) (6.1) (9.1) (12.2) (15.2) (18.3) (21.3) (24.4) (27.4) (30.5) (38.1) (45.7) (53.3) (61.0)
1/2 0.622 175 120 97 82 73 66 61 57 53 50 44 40 37 35
(4.96) (3.40) (2.75) (2.32) (2.07) (1.87) (1.73) (1.61) (1.50) (1.42) (1.25) (1.13) (1.05) (0.99)
3/4 0.824 360 250 200 170 151 138 125 118 110 103 93 84 77 72
(10.2) (7.08) (5.66) (4.81) (4.28) (3.91) (3.54) (3.34) (3.11) (2.92) (2.63) (2.38) (2.18) (2.04)
1 1.049 680 465 375 320 285 260 240 220 205 195 175 160 145 135
(19.3) (13.2) (10.6) (9.06) (8.07) (7.36) (6.80) (6.23) (5.80) (5.52) (4.96) (4.53) (4.11) (3.82)
1 1/4 1.380 1400 950 770 660 580 530 490 460 430 400 360 325 300 280
(39.6) (26.9) (21.8) (18.7) (16.4) (15.0) (13.9) (13.0) (12.2) (11.3) (10.2) (9.20) (8.50) (7.93)
1 1/2 1.610 2100 1460 1180 990 900 810 750 690 650 620 550 500 460 430
(59.5) (41.3) (33.4) (28.0) (25.5) (22.9) (21.2) (19.5) (18.4) (17.6) (15.6) (14.2) (13.0) (12.2)
2 2.067 3950 2750 2200 1900 1680 1520 1400 1300 1220 1150 1020 950 850 800
(112) (77.9) (62.3) (53.8) (47.6) (43.0) (39.6) (36.8) (34.5) (32.6) (28.9) (26.9) (24.1) (22.7)
2 1/2 2.469 6300 4350 3520 3000 2650 2400 2250 2050 1950 1850 1650 1500 1370 1280
(178) (123) (99.7) (85.0) (75.0) (68.0) (63.7) (58.0) (55.2) (52.4) (46.7) (42.5) (38.8) (36.2)
3 3.068 11000 7700 6250 5300 4750 4300 3900 3700 3450 3250 2950 2650 2450 2280
(311) (218) (177) (150) (135) (122) (110) (105) (97.7) (92.0) (83.5) (75.0) (69.4) (64.6)
4 4.026 23000 15800 12800 10900 9700 8800 8100 7500 7200 6700 6000 5500 5000 4600
(651) (447) (362) (309) (275) (249) (229) (212) (204) (190) (170) (156) (142) (130)
Table 3 - Gas Pipe Size
PIPE SIZING
To provide adequate gas pressure to the gas unit heater,
size the gas piping as follows:
1. Find the cu. ft./hr. by using the following formula:
Cu. ft./hr. =
Input BTU/Hr.
1000
2. Refer to Table 3. Match “Length of Pipe in Feet”
with appropriate “Gas Input - Cu. Ft./Hr.” fi gure. This
fi gure can then be matched to the pipe size at the
top of the column.
Example:
It is determined that a 67 foot (20.4m) run of gas
pipe is required to connect a 200 MBTU gas unit
heater to a 1,000 BTU/cu ft. (0.29kW) natural gas
supply.
200,000 BTU/Hr
= 200 Cu. ft./hr.
1,000 BTU/cu. ft.
Using Table 3, a 1 inch pipe is needed.
NOTE: See General Safety Information section for
English/Metric unit conversion factors.