AAON RZ Series, Установка, эксплуатация и обслуживание

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Table 25 - Propane (kBtu/hr) Maximum Piping Capacities
Specific Gravity = 1.52, Supply Pressure = 11” w.c., Pressure Drop, 0.5” w.c.
Pipe Size
Length of Pipe
20 ft 50 ft. 100 ft. 150 ft. 200 ft.
1-1/4” 1495 910 630 510 435
1-1/2” 2295 1415 975 785 665
2”
4330 2645 1810 1495 1280
2-1/2” 7045 4340 2990 2410 2080
3”
12510 7705 5305 4280 3615
4”
25520 15730 10830 8735 7380
Do not use gas piping smaller than unit gas
connections. Natural gas pipe runs longer
than 20 feet and propane gas pipe runs longer
than 50 feet may require a larger supply pipe
than the unit connection size. Some utility
companies may also require pipe sizes larger
than the minimum sizes listed.
Piping Sizing Example
A 100 ft pipe run is needed for a 1710 MBH
natural gas heater. The natural gas has a
rating of 1000 BTU/ft
3 and a specific gravity
of 0.6 (Obtain these values from the local gas
supplier.)
 
BTU
ft
MBH
1000
1710
3
1710 ft 3 /hr
From the natural gas maximum capacities
table, at 100 ft and 1710 ft
3 /hr the required
minimum pipe size is 2-1/2”.
A 100 ft pipe run is needed for a 800 MBH
propane gas heater.
800
MBH = 800 kBtu/hr
From the propane gas maximum capacities
table, at 100 ft and 800 kBtu/hr the required
minimum pipe size is 1-1/2”.
Inlet and Manifold Pressures
For natural gas units, the minimum inlet gas
pressure to the unit is 6” w.c. and maximum
inlet gas pressure to the unit is 10.5” w.c. For
propane units, the minimum
inlet gas
pressure to the unit is 11” w.c. and the
maximum inlet gas pressure to the unit is 13”
w.c. A field provided 1/8” NPT pressure tap
is required to be installed in the piping just
upstream of the shutoff valve for test gage
connection to allow checking of the gas
supply pressure at the unit.
A factory installed pressure tap on the outlet
end of the gas valve can be used to verify a
manifold pressure of 3.5” w.c. for natural gas,
or 10.5” w.c. for propane.
Gas Pressure Regulator & Overpressure
Protection Device
A gas pressure regulator shall be installed if
natural gas supply pressure to the unit is
greater than 10.5” w.c. and less than 2 psi
(55.4” w.c.) and if propane gas supply
pressure is greater than 13” w.c. and less than
2 psi (55.4” w.c.). Regulators shall comply
with the latest edition of the Standard for Line
Pressure Regulators, ANSI Z21.80/CSA
6.22.
Heater must be disconnected from the
gas supply piping during pressure
testing of the supply piping system with
pressures in excess of ½ psi. Gas
valves can be damaged if subjected to
more than ½ psi.
CAUTION