National boilers, radiators, and specialties: catalog no26 . Combination Gas and Coal Heating Gas and coal boilers can be conveniently yoked together andoperated either separately or as one unit for heating such an arrangement both boilers can be utilized in extremelycold weather or the coal boiler is ready for instant service inthe event of any shortage in gas or reduction in gas pressure. Gas Service Regulators With removable seat and valveand adjustable stem. Simple Compact Durable Sensitive Powerful. Size, Inches 34 1 IH m 2 Capacity, cubic feet. List without Mercury
National boilers, radiators, and specialties: catalog no26 . Combination Gas and Coal Heating Gas and coal boilers can be conveniently yoked together andoperated either separately or as one unit for heating such an arrangement both boilers can be utilized in extremelycold weather or the coal boiler is ready for instant service inthe event of any shortage in gas or reduction in gas pressure. Gas Service Regulators With removable seat and valveand adjustable stem. Simple Compact Durable Sensitive Powerful. Size, Inches 34 1 IH m 2 Capacity, cubic feet. List without Mercury with Mercury Seal 500 $7,00 535 $ 750$ 1860$ 4200$ 32 NATIONAL BOILER RATINGS Ratings The ratings of National Boilers are based upon tests madewith anthracite coal and provide that all piping (mains andrisers, flow and return) in addition to the direct radiation to beused, shall be figured as radiating surface in estimating thesize of boiler required. When a pipe coil or cast-iron section is introduced into thefirepot for the purpose of heating water for domestic use, addi-tional capacity should be figured in determining size of boiler,viz., in the case of steam boilers, 1)4 square feet of directradiation for each gallon of water to be thus heated,and in the case of water boilers, 2 square feet of directradiation for each gallon of water to be thus heated,according to the capacity of the tank to which coil or sectionis connected. When indirect radiation is to be used, not le
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectsteambo, bookyear1920
