Gas Supply Piping - Mestek SEPARATED COMBUSTION GAS FIRED PROPELLER UNIT HEATER Installation Instructions & Parts List

To avoid equipment 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 unit gas valve to excessive pressure
and damage.
PIPE SIZING
To provide adequate gas pressure at the gas unit
heater, size the gas piping as follows:
1. Find the cu ft/hr by using the following formula:
Input Btu/Hr.
Cu ft/hr =
1000
2. Refer to Table 3. Match length of pipe in feet with
appropriate "Gas Input - Cu Ft/Hr" figure. This
fi gure can then be matched to the pipe size at the
left of the table.
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 (0.29 kW) 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.
NOTICE: See General Safety Information section for
English/SI (metric) unit conversion factors.
Table 3 - Gas Pipe Size
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,
Nominal
Iron Internal
10 20
Pipe Size Dia.
Inches Inches (3.0) (6.1)
1/2 0.622 175 120
(4.96) (3.40)
3/4 0.824 360 250
(10.2) (7.08)
1 1.049 680 465
(19.3) (13.2)
1-1/4 1.380 1400 950
(39.6) (26.9)
1-1/2 1.610 2100 1460
(59.5) (41.3)
2 2.067 3950 2750
(112) (77.9)
2-1/2 2.469 6300 4350
(178) (123)
3 3.068 11000 7700
(311) (218)
4 4.026 23000 15800
(651) (447)
1. Determine the required Cu. Ft. / Hr. by dividing the rated heater input by 1000. For SI / Metric measurements: Convert unit Btu. / Hr. to
kilowatts. Multiply the units input (kW) by 0.0965 to determine Cubic Meters / Hour.
from the table. 3. FOR PROPANE GAS: Multiply the Cu. Ft. / Hr. value by 0.633; then use the table.
factors listed in General Safety section for more SI unit measurements/conversions.

GAS SUPPLY PIPING

and a Pressure Drop of 0.5 Inch Water Column (124.4 Pa)
(Based on a 0.60 Specifi c Gravity Gas)
Length of Pipe, Feet (meters)
30 40 50 60
(9.1) (12.2) (15.2) (18.3)
97 82 73 66
(2.75) (2.32) (2.07) (1.87)
200 170 151 138
(5.66) (4.81) (4.28) (3.91)
375 320 285 260
(10.6) (9.06) (8.07) (7.36)
770 660 580 530
(21.8) (18.7) (16.4) (15.0)
1180 990 900 810
(33.4) (28.0) (25.5) (22.9)
2200 1900 1680 1520
(62.3) (53.8) (47.6) (43.0)
3520 3000 2650 2400
(99.7) (85.0) (75.0) (68.0)
6250 5300 4750 4300
(177) (150) (135) (122)
12800 10900 9700 8800
(362) (309) (275) (249)
NOTICE: If more than one gas unit heater is to be
served by the same piping arrangement, the total
cubic feet per hour input and length of pipe must
be considered.
NOTICE: If the gas unit heater is to be fi red with LP
gas, refer to Table 3 and/or consult the 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
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 HEATER; AND THAT IT IS PROPERLY
CONNECTED TO PROPANE GAS SUPPLY SYSTEM.
Before any connection is made to an existing line
supplying other gas appliances, contact the local gas
company to make certain that the existing line is of
adequate size to handle the combined load.
70 80 90 100
(21.3) (24.4) (27.4) (30.5)
61 57 53
(1.73) (1.61) (1.50) (1.42)
125 118 110 103
(3.54) (3.34) (3.11) (2.92)
240 220 205 195
(6.80) (6.23) (5.80) (5.52)
490 460 430 400
(13.9) (13.0) (12.2) (11.3)
750 690 650 620
(21.2) (19.5) (18.4) (17.6)
1400 1300 1220 1150
(39.6) (36.8) (34.5) (32.6)
2250 2050 1950 1850
(63.7) (58.0) (55.2) (52.4)
3900 3700 3450 3250
(110) (105) (97.7) (92.0)
8100 7500 7200 6700
(229) (212) (204) (190)
2. FOR NATURAL GAS: Select the pipe size directly
7
125 150 175
(38.1) (45.7) (53.3)
50 44 40 37
(1.25) (1.13) (1.05)
93 84 77
(2.63) (2.38) (2.18)
175 160 145
(4.96) (4.53) (4.11)
360 325 300
(10.2) (9.20) (8.50)
550 500 460
(15.6) (14.2) (13.0)
1020 950 850
(28.9) (26.9) (24.1)
1650 1500 1370
(46.7) (42.5) (38.8)
2950 2650 2450
(83.5) (75.0) (69.4)
6000 5500 5000
(170) (156) (142)
4. Refer to the metric conversion
200
(61.0)
35
(0.99)
72
(2.04)
135
(3.82)
280
(7.93)
430
(12.2)
800
(22.7)
1280
(36.2)
2280
(64.6)
4600
(130)