Munchkin Gas-Fired Hot Water Boiler manual Part 8 GAS Piping, GAS Connection, GAS Table

GAS-FIRED BOILER Boiler Manual

PART 8: GAS PIPING

WARNING

Failure to follow all precautions could result in fire, explosion or death!

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 mini- mum of 3.5" 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.

WARNING

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 ½" with a factory installed 3/4" bell reducer. Do not remove this ¾" x ½" bell reducer! It is mandatory that this fitting is used for connection to a field fabricated drip leg as shown in the illustration above per the National Fuel Gas Code. You must ensure that the entire gas line to the connection at the Munchkin is no smaller than ¾". Once all the inspections have been performed, the piping must be leak tested. If the leak test requirement is a higher test pres- sure 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 fac- tory and field-installed gas cocks. This will pre- vent high pressure. Failure to do so may dam- age 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

a c c o r d a n c e w i t h s t a t e a n d l o c a l requirements.

C. GAS TABLE

Refer to Table 8.1 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 8-1 (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
3/4	.824	278		190	152	130	115	105	96		BTU'S
1	1.049	520		350	285	245	215	195	180		PER
1 1/4	1.380	1,050		730	590	500	440	400	370		HOUR
1 1/2	1.610	1,600		1,100	890	760	670	610	560	}x1,000
			80	90	100	125	150	175	200
3/4	.824	90		84	79	72	64	59	55		BTU'S
1	1.049	170		160	150	130	120	110	100		PER
1 1/4	1.380	350		320	305	275	250	225	210		HOUR
1 1/2	1.610	530		490	460	410	380	350	320	}x1,000

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 removing the cap and installing the manometer. The gas pressure must remain between 3.5" and 14" during stand-by (static) mode and while in operating (dynamic) mode. If an in-line regulator is used, it must be a minimum of 10 feet from the Munchkin. It is very important that the gas line is properly purged by the gas supplier or utility. Failure to properly purge the lines or improper line sizing, will result in ignition failure. This problem is especially noticeable in NEW LP installations and also in empty tank situations. This can also occur when a utility company shuts off

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