Navien NHB Series, Installation & Operation Manual

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50 Connecting the Gas Supply
Maximum Liquefied Propane Delivery Capacity
In Thousands of BTU/H (0.5 in WC pressure drop)
Pipe Size
Length (including fittings)
10 ft
(3 m) 20 ft
(6 m) 30 ft
(9 m) 40 ft
(12 m) 50 ft
(15 m) 60 ft
(18 m) 80 ft
(24 m) 100 ft
(30 m) 125 ft
(38 m) 150 ft
(45 m) 175 ft
(53 m) 200 ft
(60 m) 250 ft
(76 m)
3
/
4
in 608 418 336 287 255 231 212 197 185 175 155 140 129
1 in 1,150 787 632 541 480 434 400 372 349 330 292 265 243
1 1
/
4
in 2,350 1,620 1,300 1,110 985 892 821 763 716 677 600 543 500
1 1 /
2
in 3,520 2,420 1,940 1,660 1,480 1,340 1,230 1,140 1,070 1,010 899 814 749
2 in 6,790 4,660 3,750 3,210 2,840 2,570 2,370 2,200 2,070 1,950 1,730 1,570 1,440
4.2 Measuring the Inlet Gas Pressure
WARNING
The boiler cannot function properly without sufficient inlet gas pressure. Measuring the inlet gas pressure should be performed by a
licensed professional only.
Ɣ
The inlet gas pressure must be maintained between 3.5 in and 10.5 in WC for natural gas and between 8.0 in and 13.5 in WC for liquefied
propane.
Ɣ
The appliance and its individual shutoff valve must be disconnected from the gas supply piping system during any pressure testing of that
system at test pressures in excess of
1 /
2
psi (3.5 kPa).
Ɣ
The appliance must be isolated from the gas supply piping system by closing its individual manual shutoff valve during any pressure testing
of the gas supply piping system at test pressures equal to or less than
1 /
2
psi (3.5 kPa).