AAON RQ-006 - Manual (Page 42)

42
After verifying gas inlet pressure and
manifold pressure the service technician
must time the gas flow rate through the gas
meter with a stopwatch to verify the gas
input rate.
Unit nameplate input rate value has been
calculated at the altitude where the unit was
shipped. Above 2,000 ft the input rate is
adjusted 4% for every 1,000 ft.
Figure 20 - RQ Series Gas Heat Exchanger
Maximum Piping Capacities
Table 6 - Natural Gas (ft
3
/hr)
- Specific Gravity = 0.6, Supply Pressure ≤ 0.5 psi, Pressure Drop = 0.5” w.c.
Pipe Size
Length of Pipe
20 ft 50 ft. 100 ft. 150 ft. 200 ft.
1/2” 120 73 50 40 35
3/4” 250 151 103 84 72
1”
465 285 195 160 135
1-1/4” 950 580 400 325 280
1-1/2” 1460 900 620 500 430
2”
2750 1680 1150 950 800
2-1/2” 4350 2650 1850 1500 1280
Table 7 - Propane (kBtu/hr)
- 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 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 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