GAS CONNECTION

A. GAS CONNECTION

The gas supply shall have a maximum inlet pressure of less than 14" water column (350 mm), ½ pound pressure (3.5 kPa), and a minimum of 7" water column. The entire piping system, gas meter and regulator must be sized properly to prevent pressure drop greater than 0.5" as stated in the National Fuel Gas Code. This information is listed on the

rating plate. It is very important that you are connected to the type of gas as noted on the rating plate. "LP" for liquefied petroleum,

propane gas or, "Nat" natural or city gas. All

gas connections must be approved by the local gas supplier, or utility in addition to the governing authority, prior to turning the gas supply on. The nipple provided is 1¼" and it is mandatory that a 1 x 1¼" reducing coupling (provided) is used, threaded into the branch of a 1¼" tee, and a drip leg fabricated, as per the National Fuel Gas code. You must ensure that the entire gas line to the connection at the Munchkin is no smaller than 1¼". Once all the inspections have been performed, the piping must be leak tested. If the leak test requirement is a higher test pressure than the maximum inlet pressure, you must isolate the Munchkin from the gas line. In order to do this, you must shut the gas off using factory and field-installed gas cocks (following the lighting instructions in Part 6 Section B.) This will prevent high pressure. Failure to do so may damage the gas valve. In the event the gas valve is exposed to a pressure greater than ½ PSI, 14" water column, the gas valve must be replaced.

Never use an open flame (match, lighter, etc.) to check gas connections.

B.GAS PIPING

1.Run the gas supply line in accordance with all applicable codes.

2.Locate and install manual shutoff valves in accordance with state and local requirements.

C.GAS TABLE

Refer to Table (1) to size the supply piping to minimize pressure drop between meter or regulator and unit.

Maximum Capacity of Pipe in Cubic Feet of Gas per Hour for Gas Pressures of 0.5 psi or Less and a Pressure Drop of 0.3 Inch water Column

(TABLE 1)

 

 

 

(Based on a 0.60 Specific Gravity Gas)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Nominal

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Iron Pipe

Internal

 

 

 

 

Length of Pipe (Feet)

 

 

 

 

 

 

 

 

 

Size

Diameter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(inches)

(inches) 10

20

30

40

50

60

70

80

90

100

125

150

175

200.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3/4

.824

278

190

152

130

115

105

96

90

84

79

72

64

59

55}

BTU'S

1

1.049

520

350

285

245

215

195

180

170

160

150

130

120

110

100}

PER

1 1/4

1.380

1,050

730

590

500

440

400

370

350

320

305

275

250

225

210}

HOUR

1 1/2

1.610

1,600

1,100

890

760

670

610

560

530

490

460

410

380

350

320}

X 1,000

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

It is recommended that a soapy solution be used to detect leaks. Bubbles will appear on the pipe to indicate a leak is present. The gas piping must be sized for the proper flow and length of pipe, to avoid pressure drop. Both the gas meter and the gas regulator must be properly sized for the total gas load. If you experience a pressure drop greater than 1" WC, the meter, regulator or gas line is undersized or in need of service. You can attach a manometer to the incoming gas drip leg, by

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Munchkin 399M manual GAS Connection, GAS Piping, GAS Table