NTI INSTALLATION MANUALS

Part 8 - Gas Connections

WARNING

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. 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. NOTICE

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 speci ed 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 speci cations for actual delivery capacity. The DOE standard for Natural Gas is 1100 BTU/ft 3 . Contact the local gas supplier for actual BTU/ft 3 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 speci c gravity for natural gas.

Length of Pipe (Feet)

BTU’s Per Hour x 1,000

Pipe Size (in.)

10

20

30

40

50

60

80

100 150 200

3/4

360

247

199

170

151

137

117

104

83

71

Schedule 40 Metallic Pipe

1

678

466

374

320

284

257

220

195

157 134

1 1/4

1390

957

768

657

583

528

452

400

322 275

1 1/2

2090 1430 1150

985

873

791

677

600

482 412

(0.60 Speci c Gravity, 0.5 WC Pressure Drop)

2

4020 2760 2220

1900 1680 1520 1300 1160 928 794

3

11300 7780 6250

5350 4740 4290 3670 3260 2610 2240

4

23100 15900 12700 10900 9660 8760 7490 6640 5330 4560

Table 22 - 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. Install the factory supplied 3/4” NPT gas adapter and gasket onto the gas connection of the boiler. NOTE: The boiler gas connection is a straight thread and seals via the factory supplied gasket to the factory supplied 3/4” NPT gas adapter. Only use Te on tape or thread sealant on the male end of the 3/4” NPT gas adapter, not on the boiler connection. 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. NOTE: The pipe size must not be less than ¾”. NOTE: DO NOT USE 1/2” quick ex gas lines! Doing so will result in improper appliance operation. 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 72. 5. A manual gas shut-o valve should be installed in the gas supply line close to the boiler. See Figure 72. 6. To facilitate any future maintenance, it is also recommended that an approved gas union tting be installed in the supply line between the shut-o valve and the ¾” NPT connection on the boiler.

Manual Gas Shut-o Valve

Sediment trap

Adapter

Union

Figure 72 - Gas Line with Shut-O and Sediment Trap Detail

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