18
I-EEDU (02-21) 150492-A
INSTALLATION—CONTINUED
Piping Connections
Gas Supply Pressure
The unit is equipped for a maximum gas supply pressure of 1/2 psi, 3 .4 kPa, or 14 IN WC .
NOTES:
Supply pressure higher than 1/2 psi requires the installation of an additional service regulator
external to the unit.
PRESSURE TESTING SUPPLY PIPING
• Test pressures
above
1/2 psi—disconnect the heater and manual valve from the gas supply line
to be tested. Cap or plug the supply line.
• Test pressures
below
1/2 psi—before testing, close the manual valve on the heater.
Gas Supply Piping
⚠ DANGER ⚠
• 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.
• 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.
•
All piping must be in accordance with requirements outlined in the National Fuel Gas Code ANSI/Z223 .1 (latest
edition) or CSA-B149 .1 and B149 .2 (refer to
section) .
•
Gas supply piping installation shall conform with good practice and with local codes .
•
Duct furnaces are orificed for operation with natural gas having a heating value of 1,000 (±50) BTU per cubic foot
or with propane gas having a heating value of 2,500 (±100) BTU per cubic foot . Sizing of gas supply lines depends
on piping capacity and is based on cubic feet per hour based on a 0 .3 IN WC pressure drop, a 0 .6 specific gravity
for natural gas at 1,000 BTU per cubic feet, and a 1 .6 specific gravity for propane at 2,550 BTU per cubic feet . If
the gas at the installation does not meet this specification, consult the factory for proper orificing .
•
Variables for sizing gas supply lines are listed in
Table 11
. When sizing supply lines, consider possibilities of future
expansion and increased requirements . Refer to National Fuel Gas Code for additional information on line sizing .
Table 11. Gas Supply Line Sizes
Length
of Pipe
(Feet)
Diameter of Pipe (Inches)
1/2
3/4
1
1-1/4
1-1/2
2
Natural
Gas
Propane Natural
Gas
Propane Natural
Gas
Propane Natural
Gas
Propane Natural
Gas
Propane Natural
Gas
Propane
Cubic Feet per Hour
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
