Gas piping and pressures, Gas connection size, Sizing gas supply line – Thomas & Betts UDAP User Manual
Page 12
Form RZ-NA I-UDA, P/N 195673 Rev 5, Page 12
Gas Connection (inches)
30
45
60
75
100 125 150 175 200 225 250 300 350 400
Natural
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
3/4
3/4
3/4
3/4
3/4
Propane
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
3/4
3/4
3/4
3/4
3/4
Gas Connection Size
WARNING: This appliance is equipped for a maximum gas
supply pressure of 1/2 pound, 8 ounces, or 14 inches water column.
Supply pressure higher than 1/2 pound requires installation of
an additional lockup-type service regulator external to the unit.
WARNING: PRESSURE TESTING SUPPLY PIPING
Test Pressures Above 1/2 PSI: Disconnect the heater and manual valve from the
gas supply line which is to be tested. Cap or plug the supply line.
Test Pressures Below 1/2 PSI: Before testing, close the manual valve on the
heater.
12. Gas Piping
and
Pressures
All piping must be in accordance with requirements outlined in the National Fuel
Gas Code ANSI/Z223.1a (latest edition) or CAN/CGA-B149.1 and B149.2 (See
Paragraph 2). Gas supply piping installation should conform with good practice
and with local codes. Support gas piping with pipe hangers, metal strapping, or
other suitable material; do not rely on the heater to support the gas pipe.
The heater is orificed for operation with natural gas having a heating value of 1000
(± 50) BTUH per cubic ft or propane gas with a heating value of 2500 (± 100)
BTUH per cubic ft. If the gas at the installation does not meet these specifications,
consult the factory for proper orificing.
Pipe joint compounds (pipe dope) shall be resistant to the action of liquefied petro-
leum 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
system, as shown in FIGURE 10. Installation of a trap with a minimum 3" (76mm)
drip leg is required.
The unit is equipped with a nipple that extends outside the cabinet. The gas con-
nection is either 1/2” or 3/4”.
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.
Sizing
Gas
Supply
Line
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.