Measuring The Inlet Gas Pressure - Navien NFB-175 Mode D'emploi

Maximum Liquefied Propane Delivery Capacity
In Thousands of BTU/H (0.5 in WC pressure drop)
Length (including fittings)
Pipe Size
10 ft 20 ft
(3 m) (6 m)
/ in 291 200
1
2
/ in 608 418
3
4
1 in 1,150 787
1 / in 2,350 1,620
1
4
1 / in 3,520 2,420
1
2
2 in 6,790 4,660

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.
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.
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
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
30 ft 40 ft 50 ft
(9 m) (12 m) (15 m)
160 137 122
336 287 255
632 541 480
1,300 1,110 985
1,940 1,660 1,480
3,750 3,210 2,840
/ psi (3.5 kPa).
1
2
60 ft 80 ft 100 ft
(18 m) (24 m) (30 m)
110 101 94
231 212 197
434 400 372
892 821 763
1,340 1,230 1,140
2,570 2,370 2,200
/ psi (3.5 kPa).
1
2
125 ft 150 ft 175 ft
(38 m) (45 m) (53 m)
89 84 74
185 175 155
349 330 292
716 677 600
1,070 1,010 899
2,070 1,950 1,730
Connecting the Gas Supply
200 ft 250 ft
(60 m) (76 m)
67 62
140 129
265 243
543 500
814 749
1,570 1,440
49