Rinnai RH180 Installation Fundamentals page 36

Gas Supply Sizing Procedure
Using the row for 60 ft on this
table, you can now determine
pipe sizes.
1. Outlet A, section
to 30,000 Btu. This section
requires ½" pipe minimum.
2. Outlet B, Section
up to 75,000 Btu. This section
requires ¾" pipe minimum.
3. Outlets C and D,
share a common supply pipe
which can draw up to a total of
191,300 Btu. This section
requires 1" pipe minimum.
10 ft.
Point of Delivery
(gas meter)
36
Outlet C
RH180
1, can draw up 91,300 Btu/hr
2, can draw
section 3,
4.
10 ft.
5.
20 ft.
Outlet D
furnace
100,000 Btu/hr
3.
15 ft.
15 ft.
10 ft.
2.
Outlet B
range/oven
75,000 Btu/hr
Schedule 40 Metallic Pipe, Natural Gas, less than 2 psi inlet
pressure, 0.5" w.c. pressure drop, 0.60 specific gravity.
Pipe Size (in.)
Nominal: ½ ¾
Length Capacity in Cubic Feet of Gas per Hour
(ft)
60 65 137
4. Section 4 is supplying outlets A, C and D.
These outlets can draw up to 221,300 Btu.
This section requires 1" pipe minimum.
5. Section 5 is supplying all appliances. The
total Btu load for the home is 296,300 Btu.
This section requires 1 ¼" pipe minimum.
1.
5 ft.
1 1 ¼ 1 ½
(CFH=Btu/1000)
257 528 791
Outlet A
gas fireplace
30,000 Btu/hr