Gas Supply And Piping; Figure 15 Proper Piping Practice - Bard W24G4 Installation Instructions Manual

18. GAS SUPPLY AND PIPING

General Recommendations
1. Be sure the gas line complies with the local codes
and ordinances, or in their absence with the
National Fuel Gas Code, ANSI Z223.1, or Natural
Gas Installation Code, CAN/CGA B149.1, or
Propane Installation Code B149.2, latest edition.
2. A sediment trap or drip leg must be installed in the
supply line to the furnace.
3. A ground joint union shall be installed in the gas
line adjacent to and upstream from the gas valve
and downstream from the manual shut-off valve.
4. An 1/8" NPT plugged tapping accessible for test
gauge connection shall be installed immediately
upstream of the gas supply connection to the
furnace for the purpose of determining the supply
gas pressure. This can be omitted if local codes
permit use of plugged tapping in gas valve inlet.
5. Install listed manual shut-off valve in the supply
gas line external to and immediately upstream of
the furnace (see Figure 14).
6. Use steel or wrought iron pipe and fittings.
7. DO NOT thread pipe too far. Valve distortion or
malfunction may result from excess pipe within
the control. Use pipe joint compound resistant to
the action of liquefied petroleum gases on male
threads only. DO NOT use Teflon tape. See Table
8 and Figure 15.
TABLE 8
Length of Standard Pipe Threads (Inches)
Effective Length
Pipe Size
of Thread
3/8
3/4 1/2 – 9/16
1
FIGURE 15
Proper Piping Practice
Manual 2100-721B
Page 28 of 54
Overall Length of
Thread
1/2 9/16
13/16
9/16 1
MIS-897
8. Refer to Table 9 for gas pipe sizes for natural gas.
If more than one appliance is supplied from a
single line size, capacity must equal or exceed the
combined input to all appliances, and the branch
lines feeding the individual appliances properly
sized for each input.
THIS PRODUCT MUST BE GAS PIPED
BY A LICENSED PLUMBER OR GAS
FITTER IN THE COMMONWEALTH OF
MASSACHUSETTS.
TABLE 9
Gas Pipe Sizes – Natural Gas
Length
BTU per Hour Input Pipe Size
of Pipe -
Feet
1/2"
10 132,000 278,000
20 92,000 190,000
30 73,000 152,000
40 63,000 130,000
50 56,000 115,000
60 50,000 105,000
70 46,000 96,000
80 43,000 90,000
100 38,000 79,000
Checking the Gas Piping
Before turning gas under pressure into piping, all
openings from which gas can escape should be closed.
Immediately after turning on gas, the system should be
checked for leaks. This can be done by watching the
1/2 cubic foot test dial, allowing 4 minutes to show any
movement, soaping each pipe connection and watching
for bubbles. If a leak is found, make the necessary
repairs immediately and repeat the above test. The
furnace must be isolated from the gas supply piping
system by closing the manual shut-off valve on the
combination gas control valve during pressure testing
of the gas supply piping system at pressures up to 1/2
PSIG. The furnace and its individual shut-off valve must
be disconnected from supply piping and supply piping
capped during any pressure testing of supply piping
system at test pressures in excess of 1/2 PSIG.
Defective pipes or fittings should be replaced and
not repaired. Never use a flame or fire in any form to
locate gas leaks; use a soap solution.
After the piping and meter have been checked
completely, purge the system of air. DO NOT bleed air
inside the furnace. Be sure to check and relight all
the gas pilots on other appliances that may have been
extinguished because of interrupted gas supply.
Pipe Capacity -
3/4" 1" 1-1/4"
520,000 1,050,000
350,000 730,000
285,000 590,000
245,000 500,000
215,000 440,000
195,000 400,000
180,000 370,000
170,000 350,000
150,000 305,000