Part 8 - Gas Connections; Gas Pipe Sizing Tables; Gas Pipe Sizing; Natural Gas Pipe Sizing - NTI FTVN085 Installation Start-Up Maintenance

WARNING
FIRE AND/OR EXPLOSION HAZARD
To avoid serious injury or death, the gas line
installation and the gas line inlet pressure test
must be done by a licensed professional.
Ensure the gas on which the boiler will operate is the same type specified
on the rating plate (natural gas or LP gas). This boiler must be converted
to propane operation. Follow Gas Conversion Manual instructions
(separate document). Failure to follow these instructions could result in
property damage, personal injury, or death.
A. Gas Pipe Sizing Tables

1. Gas Pipe Sizing

This information is for reference use only. Refer to gas pipe manufacturer
specifications for actual delivery capacity. The DOE standard for Natural
3
Gas is 1100 BTU/ft . Contact the local gas supplier for actual BTU/ft
rating.

2. Natural Gas Pipe Sizing

The following tables list maximum capacity of pipe in cubic feet of
gas per hour for gas pressures of 14" or less and a pressure drop of 0.5
inches water column, based on a 0.60 specific gravity for natural gas.
Pipe Size (in.)
10
3/4
360
1
678
1 1/4
1390
1 1/2
2090
2 4020
3 11300
4 23100
Table 21 - Natural Gas Delivery Capacity - Refer to ANSI Z223.1 - National Fuel Gas Code, Latest Edition

3. LP (Liquid Propane) Gas Pipe Sizing

Contact gas supplier to size pipes, tanks, and 100% lockup gas pressure
regulator. Adjust propane supply regulator provided by the gas
supplier for 14 inches w.c. maximum pressure.
B. Gas Connection Requirements
1. The gas connection fitting is ¾" NPT.
NOTE: The gas pipe size must not be less than ¾".
NOTE: DO NOT USE 1/2" quick flex gas lines! Doing so will result in
improper appliance operation.
2. The supply line must be sized for the maximum input of the boiler
being installed. If there are additional gas appliances on the main
supply line, measure the size of the supply line according to the
COMBINED total maximum BTUH draw for the appliances as if they
were operating at the same time.
3. Measure the length of the gas supply line from the gas meter to the
boiler. The boiler must be installed downstream of the gas meter to
ensure adequate gas supply. Use the tables in this manual or refer
to the gas line manufacturer's sizing information to determine the
correct supply pipe size.
4. The National Fuel Gas Code (NFPA 54) requires that a sediment trap
(drip leg) be installed in the gas line on boilers not so equipped.
The drip leg must be accessible, a minimum of 3" in length, and not
subject to freezing conditions. See Figure 56.
Length of Pipe (Feet)
20 30 40
247 199 170
466 374 320
957 768 657
1430 1150 985
2760 2220 1900
7780 6250 5350
15900 12700 10900
WARNING
Make sure the gas line pressures are within normal limits. Pressures
outside normal limits can result in poor performance and hazardous
operating conditions, property damage, personal injury, or death.
NOTICE
Do not operate the boiler on Natural Gas or LP gas with average sulfur
rates greater than 30 mg/m3. Doing so could result in improper
product operation and failure, and WILL VOID the boiler warranty.
3
50 60 80
151 137 117
284 257 220
583 528 452
873 791 677
1680 1520 1300
4740 4290 3670
9660 8760 7490
5. A manual gas shut-off valve should be installed in the gas supply
line close to the boiler. See Figure 56.
6. To facilitate any future maintenance, it is also recommended that an
approved gas union fitting be installed in the supply line between
the shut-off valve and the ¾" NPT connection on the boiler.
Sediment
trap
Figure 56 - Gas Line with Shut-Off and Sediment Trap Detail

Part 8 - Gas Connections

BTU's Per Hour x
100 150 200
104 83 71
195 157 134
400 322 275
600 482 412
1160 928 794
3260 2610 2240
6640 5330 4560
Manual Gas
Shut-off Valve
Union
1,000
Schedule 40
Metallic Pipe
(0.60 Specific
Gravity,
0.5 WC Pressure
Drop)
55