Smith Cast Iron Boilers GB300 warranty GAS Supply Piping, Boiler Model Risers Equalizer Header

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GB300 BOILER INSTALLATION AND OPERATION INSTRUCTIONS

CAUTION: Make up water connections must be made to the return piping, not directly to the boiler or boiler damage may result.

Locate the boiler blow off preferably opposite the return piping connections. Blow off valves must be sized equal to, or larger than, the steam relief valve. Any discharge piping is to be full size to the point of discharge.

Assemble the control tree and low water cutoff as shown in Figure 99. Use Figure 94 to locate the control tree and low water cutoff on the boiler.

Table 5	Riser, Equalizer & Header Pipe Sizes
Boiler Model		Risers	Equalizer	Header
GB300-5 to -9		1 @ 3"	1-1/2"	3"
GB300-10 to -15		2 @ 3"	2"	4"
GB300-16 to -21		3 @ 3"	3"	5"

Figure 99	Steam Control Tree
MANUAL RESET	STEAM
HIGH LIMIT	GAUGE

Table 6 should be used to ensure that the gas supply piping is sized properly. If more than one appliance is supplied by the same supply pipe, the piping must be sized based on the maximum possible demand. Do not neglect the pressure drop due to pipe fittings. Table 6 should be used in conjunction with Table 7 to ensure that the supply piping has the capacity to meet the demand.

Table 6Gas Pipe Capacity

Maximum pipe capacity in ft3/hr based on 0.60 specific gravity gas at a pressure of 0.5 psig or less and a 0.3" WC pressure drop.

Nominal				Pipe length in feet
Iron Pipe	10	20	30	40	50	60	80	100	150
Size, (in)		Maximum gas volume of pipe, (ft3/hr)
1"	520	350	285	245	215	195	170	150	120
1-1/4"	1050	730	590	500	440	400	350	305	250
1-1/2"	1600	1100	890	760	670	610	530	460	380
2"	3050	2100	1650	1450	1270	1150	990	870	710
2 1/2"	4800	3300	2700	2300	2000	1850	1600	1400	1130
3"	8500	5900	4700	4100	3600	3250	2800	2500	2000

Note:

Multiply the gas volume by 0.62 for propane flow capacity in ft3/hr. Multiply the propane flow capacity by 2500 Btu/ft3 to determine the propane Btu/hr capacity for a given pipe size and length.

PET COCK

SYPHON

OPERATIG

CONTROL

SYPHON

GAUGE

GLASS

L.W.C.O.

(OPT.)

GAS SUPPLY PIPING

WARNING: Check the boiler rating plate to make sure that the boiler is for the type of gas that will be used. If it isn’t, do not connect the boiler to the gas supply. Failure to comply with this warning can result in extensive property damage, severe personal injury or death!

The GB300(S,W) boiler comes from the factory ready to be piped to the gas supply. If for any reason the boiler is not for the type of gas available at the installation site, call the nearest Smith Cast Iron Boiler distributor to resolve the problem.

Table 7		Equivalent Pipe Length Chart
Nominal		Type of pipe fitting
Iron Pipe	90 Elbow	Tee1	Gate Valve2	Gas Cock2
Size, (in)		Equivalent pipe length, (ft)
1"	2.6	5.2	0.6	1.5
1-1/4"	3.5	6.9	0.8	1.9
1-1/2"	4.0	8.0	0.9	2.3
2"	5.2	10.3	1.2	3.0
2-1/2"	6.2	12.3	1.4	3.7
3"	7.7	15.3	1.8	4.5

Notes: 1. For flow through branch. 2. For flow at full open.

Figure 100 depicts the proper way to connect the boiler to the gas supply piping. The manual shut-off valve MUST be installed in the supply piping. It should be approximately 5 feet above the floor. Provide a sediment trap at the bottom of the vertical section of the gas supply pipe upstream of the gas controls. A ground joint union should be installed between the boiler gas controls and the supply piping. Each of these items are needed to ensure long life and ease of servicing. Always use a pipe sealant that is suitable for use with LP gas.

CAUTION: Always use a wrench on the gas valve body when making gas connections to it. Never over- tighten the piping entering the gas valve body or gas valve failure may result!