Part number 550-100-305/0118
16
AquaBalance
TM
W
ALL
M
OUNT
GAS
-
FIRED
WATER
BOILER
—
Boiler Manual
5 Gas piping — sizing gas lines
Boiler gas connection is ½” NPT. Size gas lines large
enough to provide gas to all connected appliances.
Natural Gas:
Pipe sizing for natural gas
1. Size gas piping from meter outlet to entrance of boiler in
accordance with Figure 19 and Figure 20.
2. Use total input of all connected appliances. Divide total input
in Btuh by 1,000 to obtain cubic feet per hour of natural gas.
a. Pipe lengths in Figure 19 are equivalent length of straight
pipe. Convert pipe fittings to equivalent lengths using
data from Figure 20.
b. Figure 19 is only for natural gas with specific gravity 0.60,
with a pressure drop through the gas piping as listed in
the table.
c. For additional gas pipe sizing information, refer to ANSI
Z223.1 (Natural Gas and Propane Installation Code, CSA
B149.1 and B149.2 for Canadian installations).
Natural gas supply pressure
1. Pressure required at gas valve inlet pressure port:
a. Maximum: 13” w.c. with no flow (lockup).
b. Minimum: 3.5” w.c. gas pressure, with gas flowing
(verify during boiler startup, while boiler is at high fire).
Nominal gas pressure: 7.0” w.c.
2. Install 100% lockup gas pressure regulator in supply line if
inlet pressure can exceed 13” w.c. at any time. Adjust lockup
regulator for 13” w.c. maximum.
Propane Gas:
You must follow the instructions, beginning on
page 12, to operate the boiler on propane. Failure
to comply could result in severe personal injury,
death or substantial property damage.
Pipe sizing for propane gas
1. Contact gas supplier to size pipes, tanks and 100% lockup
gas pressure regulator.
Propane supply pressure
1. Adjust propane supply regulator provided by gas supplier for
13” w.c. maximum pressure.
2. Pressure required at gas valve inlet pressure port:
a. Maximum: 13” w.c. with no flow (lockup).
b. Minimum: 3.5” w.c. gas pressure, with gas flowing
(verify during boiler startup, while boiler is at high fire).
Nominal gas pressure: 11.0” w.c.
Figure 19
Pipe capacity for 0.60 specific gravity natural
gas; pipe length is in equivalent feet
Gas
pipe
total
length,
feet
Capacity
Cubic feet per hour, natural gas, 0.60 specific gravity
Gas pressure 13” w.c. or less
Pressure drop 0.3 inches w.c.
½”
¾”
1”
1¼”
1½”
2”
2½”
10
132
278
520
1050
1600
3050
4800
20
92
190
350
730
1100
2100
3300
30
73
152
285
590
890
1650
2700
40
NA
130
245
500
760
1450
2300
50
NA
115
215
440
670
1270
2000
75
NA
105
175
360
545
1020
1650
100
NA
96
150
305
460
870
1400
150
NA
90
120
250
380
710
1130
Figure 20
Equivalent lengths of straight pipe for typical
gas line fittings
Pipe size
(inches)
Equivalent length, feet
90° Elbow
Tee
short
radius
long
radius
line
branch
½
3.6
2.2
1.7
4.2
¾
4.4
2.3
2.4
5.3
1
5.2
2.7
3.2
6.6
1¼
6.6
3.2
4.6
8.7
1½
7.4
3.4
5.6
9.9
2
8.5
3.6
7.7
12.0
2½
9.3
4.0
9.3
13.0