Gas supply sizing, Gas supply entrance – Reznor RPB Unit Installation Manual User Manual
Page 9
Form I-RPB, P/N 131782 R12, Page 9
Gas Supply
Entrance
5
-3/4
(146mm)
Condensate
Weep Holes
Install the gas supply piping so that when
the union is disconnected, the supply pipe
will not interfere with the removal of the
burner rack. (The burner rack slides out of
the control side of the furnace.)
FIGURE 5 - Gas Connection Location and Requirements
Minimum 1 (25mm) clearance
between heater access panel
and elbow or fitting
Install a 1/8 NPT plug with tap
for test gauge immediately
upstream of the gas supply
connection.
Manual shutoff valve
Installer supplies
manual shutoff,
ground unions
and shaded piping
Gas Connection to Single-Stage
Valve (Not Gas Supply Line Size)
RPB
125-250 300-400
Natural Gas
1/2"
3/4"
Propane
1/2"
1/2"
Gas Supply Sizing
Capacity of Piping
Cubic Feet per Hour based on 0.3" w.c. Pressure Drop
Specific Gravity for Natural Gas -- 0.6 (Natural Gas -- 1000 BTU/Cubic Ft)
Specific Gravity for Propane Gas -- 1.6 (Propane Gas -- 2550 BTU/Cubic Ft)
Length
Diameter of Pipe
of
1/2"
3/4"
1"
1-1/4"
1-1/2"
2"
Pipe
Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane
20'
92
56
190
116
350
214
730
445
1100
671
2100
1281
30'
73
45
152
93
285
174
590
360
890
543
1650
1007
40'
63
38
130
79
245
149
500
305
760
464
1450
885
50'
56
34
115
70
215
131
440
268
670
409
1270
775
60'
50
31
105
64
195
119
400
244
610
372
1105
674
70'
46
28
96
59
180
110
370
226
560
342
1050
641
80'
43
26
90
55
170
104
350
214
530
323
990
604
90'
40
24
84
51
160
98
320
195
490
299
930
567
100'
38
23
79
48
150
92
305
186
460
281
870
531
125'
34
21
72
44
130
79
275
168
410
250
780
476
150'
31
19
64
39
120
73
250
153
380
232
710
433
175'
28
17
59
36
110
67
225
137
350
214
650
397
200'
26
16
55
34
100
61
210
128
320
195
610
372
Note: When sizing supply lines, consider possibilities of future expansion and increased requirements.
Refer to National Fuel Gas Code for additional information on line sizing.
Duct furnaces for natural gas are orificed for operation with gas having a heating value
of 1000 (+ or - 50) BTU per cubic ft. If the gas at the installation does not meet this
specification, consult the factory for proper orificing.
Pipe joint compounds (pipe dope) shall be resistant to the action of liquefied
petroleum gas or any other chemical constituents of the gas being supplied.
Install a ground joint union and manual shutoff valve upstream of the unit control sys-
tem, as shown in
FIGURE 5. The 1/8" plugged tapping in the shutoff valve provides
connection for supply line pressure test gauge. The National Fuel Gas Code requires
the installation of a trap with a minimum 3" drip leg. Local codes may require a mini-
mum drip leg longer than 3" (typically 6").
After all connections are made, disconnect the pilot supply at the control valve and
bleed the system of air. Reconnect the pilot line and leak-test all connections by brush-
ing on a soap solution.
WARNING
All components of a gas supply system must be leak tested prior
to placing equipment in service. NEVER TEST FOR LEAKS WITH
AN OPEN FLAME. Failure to comply could result in personal
injury, property damage or death.