Gas Train Diagram - Weil-McLain SVF 1500 Manual

SVF
™
Series 1
Commercial Condensing Gas-Fired Water Boiler — Boiler Manual
Gas piping
Pipe sizing for Natural Gas
1. Size gas supply piping from meter outlet to entrance of boiler in ac-
cordance with Figure 48 and Figure 49.
2. Use the total input of all connected appliances. Divide the total input in
Btuh by 1,000 to obtain approximate cubic feet per hour of natural gas.
a. Pipe lengths in Figure 48 are equivalent lengths of straight pipe. Use
Figure 49 to determine equivalent length of fittings.
b. Figure 48 is only for natural gas with specific gravity 0.60, with a
pressure drop through the gas piping of 0.30" w.c.
c. For additional gas pipe sizing information, refer to ANSI Z223.1/
NFPA 54 - latest edition (or Natural Gas and Propane Installation
Code - CAN/CSA B149.1 for Canadian installations).
Pipe sizing for propane gas
Contact gas supplier to size pipes, tanks and 100% lockup gas pressure
regulator. Gas pipe must be properly sized with a 100% lockup gas pressure
regulator in the gas supply line. An undersized gas pipe feeding the boiler(s)
can cause problems.
Multiple boiler applications —manifolded
gas supply lines
1. Size gas supply piping as instructed above.
2. At each boiler, provide a manual shutoff gas valve, union and sediment
trap (minimum 3 inches below tee) as shown in Figure 46, page 47.
3. Ensure the piping is large enough so that the minimum pressure at
each boiler, with all connected appliances firing, will be as specified
on page 47.
Gas pressure switches
TM
SVF
1. boilers are equipped with manual reset high gas pressure and
low gas pressure switches (see Figure 47, page 47).
2. These switches are factory set and should remain at the following set-
tings:
a. High gas pressure: 14 inches w.c.
b. Low gas pressure: 2 inches w.c.
The low gas pressure switch must be manually reset (button
on front of switch) on initial startup or any time the gas supply
is turned off.

Gas Train Diagram

48
(continued)
Figure 48
Pipe capacity for natural gas
Gas supply pipe capacity (cubic feet per
Gas
pipe
total
length
(feet)
2"
10 3050
20 2100
30 1650
40 1450
50 1270
70 1050
100 870
150 710
Figure 49
Equivalent lengths of straight pipe for gas
line fittings
inches
2"
2½"
3"
4"
From Figure 47, page 47.
#1
#2
hour)
@ 0.30" w.c. pressure drop
2½" 3"
4800 8500
3300 5900
2700 4700
2300 4100
2000 3600
1700 3000
1400 2500
1130 2000
90° Elbow Tee
5.17 10.3
6.16 12.3
7.67 15.3
10.1 20.2
#3
Part number 550-100-250/0819
4"
17500
12000
9700
8300
7400
6200
5100
4100