Sterling RT - Manual (Page 11)

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GAS CONNECTIONS (continued)
For the most satisfactory piping installation, the following
procedure should be followed. Make piping layout of the
whole installation and calculate the cubic feet of gas that
each supply pipe will carry. See piping example below.
Calculate the cubic feet of gas that each supply pipe
will carry:
Btu/Hr.
1000 Btu Natural Gas/Cu. Ft.
= Cu. Ft. Per Hour of Gas to Unit (cfh)
Unit Kilowatt
37.3 Megajoules Natural Gas/Cu Meter
= Liters per second on Gas to Unit (l/s)
NOTICE: Contact your natural gas supplier for
the Btu/Cu. Ft. content of natural gas in your area.
This may be higher or lower than the nominal
1000 Btu/Cu. Ft. used in this example:
Refering to the piping example in fi gure 10, the length of
pipe from the gas meter (A) to the most remote heater
(E) is 60 feet. This distance should be used for all of the
heaters when determining the pipe size required. Based
on the column marked 60 feet in chart 3, the piping for
this example should be sized as follows:
• 450 cfh is supplied from A to B, requiring
1-1/4 inch pipe.
• 200 cfh is supplied from B to C, requiring
1 inch pipe.
Figure 10 - Example of Piping Layout for Determining Pipe Size
GAS METER
A
20 ft.
6.56 m.
20 ft.
6.56 m.
5 ft.
1.64 m.
5 ft.
1.64 m.
10 ft.
3.48 m.
B
C
D
F
E 10 ft.
3.28 m.
HEATER(S)
200 CFH
HEATER(S)
150 CFH
3588
HEATER(S)
100 CFH
D3588
• 250 cfh is supplied from B to D, requiring
1 inch pipe.
• 100 cfh is supplied from D to E, requiring
3/4 inch pipe.
• 150 cfh is supplied from D to F, requiring
1 inch pipe.
For SI calulations, refer to metric conversion chart
in general safety section of this manual.
NOTICE: If more than one gas duct furnace is to be
served by the same piping arrangement, the total cu.
ft./hr. input and length of pipe must be considered.
NOTICE: If the gas duct furnace is to be fired
with LP gas, consult local LP gas dealer for pipe
size information. Heater installation for use with
propane (bottled) gas must be made by a qualifi ed
LP gas dealer or installer. He will insure proper joint
compounds are used for making pipe connections;
that air is purged from lines; that a thorough test is
made for leaks before operating heater; and that it is
properly connected to propane gas supply system.
Before any connection is made to an existing line
supplying other gas appliances, contact the local gas
company to make certain that the existing line is of
adequate size to handle the combined load.
Check all connections with a soap solution before
leaving job.