User manual BOSCH GWH 425 HN

[. . . ] Water heaters for use with Natural and L. P. G. GWH 425 HN Flow Modulated with Electronic Ignition Suitable for heating potable water only - Not approved for space heating purposes (Intended for variable flow applications with steady cold water inlet temperatures) GWH-425-HN-N GWH-425-HN-L Warning: If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or death. Do not store or use gasoline or other flammable vapor and liquids in the vicinity of this or any other appliance. Improper installation, adjustment, alteration, service or maintenance can cause injury or property damage. For assistance or additional information consult a qualified installer, service agency or the gas supplier. [. . . ] First determine the effective length of the gas supply line by measuring the actual length of piping, and then adding 5 ft. for every elbow or "T" to the actual length. Use the charts below to determine the pipe diameter necessary to accommodate the BTU demand of the unit. If there are more gas drawing appliances on the line, size according to the maximum amount of BTU demand. FOR NATURAL GAS Maximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0. 5 Psig or less and a Pressure drop of 0. 3 in Water Column. (Based on a 0. 60 Specific Gravity Gas) Btu numbers given in thousands. Nominal Iron Pipe Size, Internal Diameter 10 32 72 132 278 520 1050 1600 3050 4800 8500 20 22 49 92 190 350 730 1100 2100 3300 5900 30 18 40 73 152 285 590 890 1650 2700 4700 40 15 34 63 130 245 500 760 1450 2300 4100 50 14 30 56 115 215 440 670 60 12 27 50 105 195 400 610 70 11 25 46 96 180 370 560 80 11 23 43 90 170 350 530 990 1600 2800 90 10 22 40 84 160 320 490 930 1500 2600 100 9 21 38 79 150 305 460 870 1400 2500 125 8 18 34 72 130 275 410 780 1250 2200 150 8 17 31 64 120 250 380 710 1130 2000 175 7 15 28 59 110 225 350 650 1050 200 6 14 26 55 100 210 320 610 980 Length of Black Iron Pipe, Feet Follow boxed numbers for piping just one 425 HN (example: 3/4" B. I. For multiple appliances combine the total btu input load and then refer to applicable chart below. inches inches 1/4 3/8 1/2 3/4 1 1 1/4 1 1/2 2 2 1/2 3 4 0. 364 0. 493 0. 622 0. 824 1. 049 1. 380 1. 610 2. 067 2. 469 3. 068 4. 026 1270 1150 1050 2000 1850 1700 3600 3250 3000 1850 1700 17, 500 12, 000 9, 700 8, 300 7, 400 6, 80 6, 200 5, 800 5, 400 5, 100 4, 500 Nominal Iron Pipe Size, 4, 100 3, 800 3500 FOR LP GAS Maximum Capacity of Pipe in Thousands of BTU per Hour of Undiluted Petroleum Gases (at 11 inches Water Column Inlet Pressure) (Based on a Pressure Drop of 0. 5 Inch Water Column). Black Iron Pipe Length of Pipe, Feet 10 20 30 40 50 60 70 96 80 89 90 83 100 78 162 307 630 976 125 69 146 275 567 866 150 63 132 252 511 787 Inches 1/2 3/4 1 1 1/4 1 1/2 2 275 189 152 567 693 315 107 732 590 220 149 121 330 229 185 622 433 346 129 114 103 267 237 217 196 185 173 504 448 409 378 346 322 103 913 834 771 724 677 155 141 127 118 108 102 299 264 239 220 204 192 1811 1606 1496 Maximum Capacity of Semi-Rigid Tubing in Thousands of BTU per Hour of Undiluted Liquified Petroleum Gases (at 11 inches Water Column Inlet Pressure) (Based on a Pressure Drop of 0. 5 Inch Water Column) Outside Diameter, Inch 3/8 1/2 5/8 3/4 7/8 Copper Length of Tubing, Feet 10 39 92 20 26 62 30 21 50 107 40 19 41 90 50 _ 37 79 131 198 60 _ 35 72 70 _ 31 67 80 _ 29 62 90 _ 27 59 95 100 _ 26 55 90 199 131 329 216 501 346 181 145 277 233 121 112 104 187 164 155 146 138 * Source National Fuel Gas Code NFPA 54, ANSI Z223. 1. 10 6 720 607 026 WATER CONNECTIONS Install the heater centrally in the building if possible and make hot water piping runs as short as possible When facing the heater, the cold water inlet will be on the right and the hot water outlet on the left. Although water piping throughout the building may be other than copper, copper or galvanized piping should be used when connecting to the heaters ½" male NPT flex connectors (follow local codes if more stringent). Plastics or other PEX type plumbing line materials are not suitable for connecting directly to the water heater. Keep water inlet pipe to no less than ½" (19. 05mm) diameter to allow the full flow capacity. If the cold and hot connections to the heater are reversed, the heater will not function. The 425 HN is provided with one flexible type connector that must be connected to the cold inlet fitting of the water valve as shown in Fig. The union end of the flexible connector should be attached to the rear inlet port of the water valve with the supplied washer gasket. No pipe dope or thread tape is to be used at this joint. The ½" flexible hot water outlet line is supplied attached to the heater. Be certain there are no loose particles or dirt in the piping. Blow out or flush the lines before connecting to the water heater. Full port valves should be installed on both the cold water supply and hot water outlet lines to facilitate servicing the heater (see Fig. For installation on a private well system with the use of a pressure tank, the lowest pressure range setting recommended is 30-50 psi (2. 07-3. 45 bar). Pipe to appropriate discharge Hot Cold Fig. 7 - Pressure Relief Valve OPERATING INSTRUCTIONS Before proceeding with the operation of the heater make sure that the system is filled with water. Open the cold water inlet supply to the heater fully. Open a hot water faucet to permit the water to fill the heater and the piping and to eliminate the air trapped in the system Close the hot water faucet after the water flows freely and all the air has escaped from the system. The water heater is now ready to operate. FOR YOUR SAFETY READ B EFORE OPERATING YOUR HOT WATER HEATER Warning: If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life. [. . . ] to damage or abuse, accident, neglect or freezing and other acts of nature; 3. to damage resulting from operation with either the flame sensor rod or overheat sensor removed; 4. to failure of the heat exchanger resulting from the operation of the water heater in a corrosive atmosphere or at water temperatures exceeding the maximum rating, or if the water heater is not supplied with potable water; 5. to defects or damage cause by any attachment or modification, including any energy-saving device. [. . . ]