GSA
Gas-Fired Steam Boilers –
Boiler Manual
15
Part Number 550-110-738/1012
5 Install gas piping
Connecting gas supply piping to boiler
1. Remove jacket front panel and see Figure 17 to pipe gas to
boiler.
a. Install drip leg at inlet of gas connection to boiler. Where
local utility requires drip leg to be extended to the floor,
use appropriate length of nipple between cap and tee.
b. Install ground joint union for servicing, when required.
c. Install manual shutoff valve in gas supply piping outside
boiler jacket when required by local codes or utility
requirements.
d. In Canada — When using manual main shutoff valve, it
must be identified by the installer.
2. Support
piping with hangers, not by boiler or
its accessories.
3. Purge all air from gas supply piping.
4. Before placing boiler in operation, check boiler and its gas
connection for leaks.
a. Close manual main shutoff valve during any pressure
testing at less than 13” w.c.
b. Disconnect boiler and gas valve from gas supply piping
during any pressure testing greater than 13” w.c.
Do not check for gas leaks with an open flame — Use
bubble test. Failure to use bubble test or check for
gas leaks can cause severe personal injury, death
or substantial property damage.
5. Use pipe dope compatible with propane gases. Apply sparingly
only to male threads of pipe joints so that pipe dope does not
block gas flow.
Failure to apply pipe dope as described in this
manual can result in severe personal injury, death
or substantial property damage.
Table 9
Pipe capacity for 0.60 specific gravity natural gas
Natural Gas:
1. See Table 9 for pipe length and diameter. Base on rated
boiler input, found on page 31 (divide by 1,000 to obtain cubic
fe
et per hour). Table 9 is only for gas with specific gravity
0.60, with a pressure drop through the gas piping of 0.30” w.c.
For additional gas pipe sizing information, see ANSI Z223.1
(B149.1 or B149.2 for Canadian installations).
2. Inlet pressure required at gas valve inlet:
• Maximum: 13” w.c.
• Minimum: 5” w.c.
• Manifold gas pressure: 3.5” w.c.
3. Install 100% lockup gas pressure regulator in supply line if
inlet pressure exceeds 13” w.c. Adjust for 13” w.c. maximum.
Propane Gas:
1. Contact gas supplier to size pipes, tanks and 100% lockup
gas pressure regulator.
2. Adjust propane supply regulator provided by gas supplier for
13” w.c. maximum pressure.
3. Inlet pressure required at gas valve inlet:
• Maximum: 13” w.c.
• Minimum: 11” w.c.
• Manifold gas pressure: 10” w.c.
Figure 17
Gas supply piping
Gas
pipe
length
(feet)
Capacity of pipe for pipe size of:
(Capacity in cubic feet gas per hour)
½”
¾”
1”
1¼”
1½”
2”
10
132
278
520
1050
1600
3050
20
92
190
350
730
1100
2100
30
73
152
285
590
860
1650
40
63
130
245
500
760
1450
50
56
115
215
440
670
1270
75
45
93
175
360
545
1020
100
38
79
150
305
460
870
150
31
64
120
250
380
710