83
Table 31 – (
Metric
)
Propane (kW) Maximum Piping Capacities
Specific Gravity = 1.52, Supply Pressure = 2.34 kpa., Pressure Drop, 0.93 mmHg
Pipe Size
(mm)
Length of Pipe
6.1 m
15.2 m
30.4 m
45.6 m
60.8 m
12.7
0.6
0.4
0.3
0.2
0.2
19
1.3
0.8
0.6
0.5
0.4
25.4
2.5
1.5
1.0
0.9
0.7
31.75
438.1
266.7
184.6
149.5
127.5
38.10
672.6
414.7
285.7
230.1
194.9
50.80
1269.0
775.2
530.5
438.1
375.1
Table 32 – (
Imperial
)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.
1/2”
189
114
78
63
55
3/4”
393
237
162
132
112
1”
732
448
307
252
213
1-1/4”
1496
913
630
511
440
1-1/2”
2299
1417
976
787
675
2”
4331
2646
1811
1496
1260
Do not use gas piping smaller than unit gas
connections. Natural gas pipe runs longer
than 6.1 meters (20 feet) and propane gas
pipe that runs longer than 15.2 meters (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 Examples
A 100 ft pipe run is needed for a 1080 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
1080
3
1080 ft
3
/hr
From the natural gas maximum capacities
table, at 100 ft and 1080 ft
3
/hr the required
minimum pipe size is 2”.
A 100 ft pipe run is needed for a 270 MBH
propane gas heater.
270
MBH
= 270 kBtu/hr
From the propane gas maximum capacities
table, at 100 ft and 270 kBtu/hr the required
minimum pipe size is 1”.
Inlet and Manifold Pressures
For natural gas units, the minimum inlet gas
pressure to the unit is 11.2 mmHg (6” w.c.)
and maximum inlet gas pressure to the unit is
19.6 mmHg (10.5” w.c.) For propane units,
the minimum inlet gas pressure to the unit is
20.6 mmHg (11” w.c.) and the maximum
inlet gas pressure to the unit is 24.3 mmHg
(13” w.c.) A field provided 0.3 cm (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 6.5 mmHg (3.5” w.c.)
Summary of Contents for RQ NextGen Series
Page 2: ......
Page 26: ...26 Figure 3 RQ Cabinet Standard and Power Exhaust Gasket Locations...
Page 40: ...40 Figure 23 Post Corner Hole Piping Figure 24 Post Back Hole Piping...
Page 88: ...88 Gas Heater Operating Instructions Figure 36 Gas Heater Instructions...
Page 95: ...95...
Page 96: ...96...
Page 105: ...105 Maintenance Log E Coated Coil...
Page 107: ...107...
