A.O. Smith BTR 120 Owner's manual

1
MODELS BTR(C)120 THRU 400A
COMMERCIAL GAS, GLASS-LINED, TANK-TYPE WATER HEATER
•INSTALLATION • OPERATION • MAINTENANCE •LIMITED WARRANTY
PLACE THESE INSTRUCTIONSADJACENT TO HEATER
AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.
500 Tennessee Waltz Parkway, Ashland City, TN 37015
Phone: [phone] Fax: [phone]
www.hotwater.com
CAUTION
TEXT PRINTED OR OUTLINED IN RED CONTAINS
INFORMATION RELATIVE TOYOUR SAFETY. PLEASE READ
THOROUGHLY BEFORE INSTALLING AND USING THIS
APPLIANCE.
Thank you for buying this energy efficient water heater from
A.O. Smith Water Products Company. We appreciate your
confidence in our product.
PRINTED IN U.S.A. 0706 PART NO. 197283-000

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BTR MODELS 120 THROUGH 400A - TABLE 1A
MODEL INPUT APPROX. GAS H VENT CONNECTIONS Approximate
RATE TANK INLET DIA INLET OUTLET ship. Weight
BTU/Hr. CAP. A B C D E F G I J TOP FRONT BACK TOP FRONT BACK STD. ASME
BTR120 120,000 BTU/Hr. 71 Gal 69.75" 4.25" 59.50" 50.87" 19.69" 19" 1/2" 51.88" 5" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 400 Lbs NA
35 Kw/Hr 268 L 177 cm 11 cm 151 cm 129 cm 50 cm 48 cm 1/2" 132 cm 13 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 182 Kg NA
BTR154 154,000 BTU/Hr 81 Gal 73.00" 4.25" 66.50" 57.87" 19.69" 19" 1/2" 59.00" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 470 Lbs NA
45 Kw/Hr 307 L 185 cm 11 cm 169 cm 147 cm 50 cm 48 cm 1/2" 150 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 213 Kg NA
BTR180 180,000 BTU/Hr 81Gal 67.50" 4.50" 62.00" 53.62" 20.50" 21" 1/2" 54.62" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 470 Lbs NA
53 Kw/Hr 307 L 171 cm 12 cm 157 cm 136 cm 52 cm 53 cm 1/2" 139 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 213 Kg NA
BTR197 199,000 BTR/Hr 100 Gal 75.00" 4.50" 70.00" 61.62" 20.50" 21" 1/2" 62.62" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 603 Lbs NA
58 kW/Hr 379 L 192 cm 12 cm 178 cm 157 cm 52 cm 53 cm 1/2" 159 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 273 Kg NA
BTR198 199,000 BTU/Hr. 100 Gal 75.00" 4.50" 70.00" 61.62" 20.50" 21" 1/2" 61.50" 6" 27.75" 1.50" 1.50" 2.00" 1.50" 1.50" 2.00" 603 Lbs NA
58 Kw/Hr 379 L 192 cm 12 cm 178 cm 157 cm 52 cm 53 cm 1/2" 150 cm 15 cm 71 cm 1.50" 1.50" 2.00" 1.50" 1.50" 2.00" 273 Kg NA
BTR199 199,000 BTU/Hr 81 Gal 67.50" 4.50" 62.00" 53.62" 20.50" 21" 1/2" 54.62" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 470 Lbs NA
58 kW/Hr 307 L 171 cm 12 cm 157 cm 136 cm 52 cm 53 cm 1/2" 139 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 213 Kg NA
BTR 200 199,000 BTR/Hr 100 Gal 72.00" 4.50" 65.13" 55.87" 19.75" 23" 1/2" 56.38" 6" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 630 Lbs 725 Lbs
58 kW/Hr 379 L 183 cm 12 cm 165 cm 142 cm 50 cm 58 cm 1/2" 143 cm 15 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 286 Kg 329 Kg
BTR 250 250,000 BTR/Hr 100 Gal 72.00" 4.50" 65.13" 55.87" 19.75" 23" 1/2" 56.38" 8" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 630 Lbs 725 Lbs
72 kW/Hr 379 L 183 cm 12 cm 165 cm 142 cm 50 cm 58 cm 1/2" 143 cm 20 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 286 Kg 329 Kg
BTR 251 251,000 BTR/Hr 65 Gal 75.00" 4.50" 65.75" 57.25" 20.00" NA 1/2" 58.75 8" 27.75" NA 1.50" 1.50" NA 1.50" 1.50" 750Lbs 862 Lbs
73 kW/Hr 246 L 191 cm 12 cm 167 cm 145 cm 51 cm NA 1/2" 149 cm 20 cm 70 cm NA 1.50" 1.50" NA 1.50" 1.50" 341 Kg 391 Kg
BTR 275 275,000 BTR/Hr 100 Gal 72.00" 4.50" 65.13" 55.87" 19.75" 23" 1/2" 56.38" 8" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 630 Lbs 725 Lbs
80 kW/Hr 379 L 183 cm 12 cm 165 cm 142 cm 50 cm 58 cm 1/2" 143 cm 20 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 286 Kg 329 Kg
BTR 305 305,000 BTR/Hr 65 Gal 75.00" 4.50" 65.75" 57.25" 20.00" NA 1/2" 58.75 8" 27.75" NA 1.50" 1.50" NA 1.50" 1.50" 750 Lbs 862 Lbs
89 kW/Hr 246 L 191 cm 12 cm 167 cm 145 cm 51 cm NA 1/2" 149 cm 20 cm 70 cm NA 1.50" 1.50" NA 1.50" 1.50" 341 Kg 391 Kg
BTR 365 365,000 BTR/Hr 85 Gal 79.50" 4.50" 70.25" 62.50" 22.50" 23” 3/4" 63.00 8" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 725 Lbs 833 Lbs
107 kW/Hr 322 L 202 cm 12 cm 178 cm 159 cm 57 cm 58 cm 3/4" 160 cm 20 cm 70 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 329 Kg 379 Kg
BTR 400 390,000 BTU/Hr 100 Gal 75.50" 4.50" 67.50" 58.25" 26.75" 23" 3/4" 59.00" 8" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 760 Lbs 874 Lbs
114 kW/Hr 379 L 192 cm 12 cm 171 cm 148 cm 68 cm 58 cm 3/4" 150 cm 20 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 345 Kg 396 Kg
BTRC MODELS 120 THROUGH 400/A - TABLE 1B
MODEL INPUT APPROX. GAS H VENT CONNECTIONS Approximate
RATE TANK INLET DIA INLET OUTLET ship. Weight
BTU/Hr. CAP. A B C D E F G I J TOP FRONT BACK TOP FRONT BACK STD. ASME
BTRC120 120,000 BTU/Hr. 71 Gal 69.75" 4.25" 59.50" 50.87" 19.69" 19" 1/2" 51.88" 5" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 400 LBS NA
35 Kw/Hr 268 L 177 cm 11 cm 151 cm 129 cm 50 cm 48 cm 1/2" 132 cm 13 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 182 Kg NA
BTRC154 154,000 BTU/Hr 81 Gal 73.00" 4.25" 66.50" 57.87" 19.69" 19" 1/2" 59.00" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 470 LBS NA
45 Kw/Hr 307 L 185 cm 11 cm 169 cm 147 cm 50 cm 48 cm 1/2" 150 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 213 Kg NA
BTRC180 180,000 BTU/Hr 76 Gal 70.50" 4.25" 63.75" 55.13" 17.75" 19" 1/2" 56.50" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 470 LBS NA
53 Kw/Hr 288 L 179 cm 11 cm 162 cm 140 cm 45 cm 48 cm 1/2" 144 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 213 Kg NA
BTRC197 199,000 BTR/Hr 95 Gal 81.50" 4.25" 74.75" 66.13" 17.75" 19" 1/2" 67.50" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 603 LBS NA
58 kW/Hr 360 L 207 cm 11 cm 190 cm 168 cm 45 cm 48 cm 1/2" 171 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 273 Kg NA
BTRC199 199,000 BTU/Hr 76 Gal 70.50" 4.25" 63.75" 55.13" 17.75" 19" 1/2" 56.50" 6" 27.75" 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 470 LBS NA
58 kW/Hr 288 L 179 cm 11 cm 162 cm 140 cm 45 cm 48 cm 1/2" 144 cm 15 cm 71 cm 1.50" 1.50" 1.50" 1.50" 1.50" 1.50" 213 Kg NA
BTRC200 199,000 BTR/Hr 100 Gal 72.00" 4.50" 65.13" 55.87" 19.75" 23" 1/2" 56.38" 6" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 630 lbs 725 lbs
58 kW/Hr 379 L 183 cm 12 cm 165 cm 142 cm 50 cm 58 cm 1/2" 143 cm 15 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 286 Kg 329 Kg
BTRC250 250000 BTR/Hr 100 Gal 72.00" 4.50" 65.13" 55.87" 19.75" 23" 1/2" 56.38" 8" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 630 lbs 725 lbs
72 kW/Hr 379 L 183 cm 12 cm 165 cm 142 cm 50 cm 58 cm 1/2" 143 cm 20 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 286 Kg 329 Kg
BTRC251 251000 BTR/Hr 65 Gal 75.00" 4.50" 65.75" 57.25" 20.00" NA 1/2" 58.8 8" 27.75" NA 1.50" 1.50" NA 1.50" 1.50" 750 lbs 862 lbs
73 kW/Hr 246 L 191 cm 12 cm 167 cm 145 cm 51 cm NA 1/2" 149 cm 20 cm 70 cm NA 1.50" 1.50" NA 1.50" 1.50" 341 Kg 391 Kg
BTRC275 275,000 BTR/Hr 100 Gal 72.00" 4.50" 65.13" 55.87" 19.75" 23" 1/2" 56.38" 8" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 630 lbs 725 lbs
80 kW/Hr 379 L 183 cm 12 cm 165 cm 142 cm 50 cm 58 cm 1/2" 143 cm 20 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 286 Kg 329 Kg
BTRC305 305,000 BTR/Hr 65 Gal 75.00" 4.50" 65.75" 57.25" 20.00" NA 1/2" 58.8 8" 27.75" NA 1.50" 1.50" NA 1.50" 1.50" 750 lbs 862 lbs
89 kW/Hr 246 L 191 cm 12 cm 167 cm 145 cm 51 cm NA 1/2" 149 cm 20 cm 70 cm NA 1.50" 1.50" NA 1.50" 1.50" 341 Kg 391 Kg
BTRC365 365,000 BTR/Hr 65 Gal 75.00" 4.50" 65.75" 57.25" 20.00" NA 3/4" 58.8 8" 27.75" NA 1.50" 1.50" NA 1.50" 1.50" 750 lbs 862 lbs
107 kW/Hr 246 L 191 cm 12 cm 167 cm 145 cm 51 cm NA 3/4" 149 cm 20 cm 70 cm NA 1.50" 1.50" NA 1.50" 1.50" 341 Kg 391 Kg
BTRC400 390,000 BTU/Hr 100 Gal 75.50" 4.50" 67.50" 58.25" 26.75" 23" 3/4" 59.00" 8" 30.25" 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 760 lbs 874 lbs
114 kW/Hr 379 L 192 cm 12 cm 171 cm 148 cm 68 cm 58 cm 3/4" 150 cm 20 cm 77 cm 1.50" 2.00" 2.00" 1.50" 2.00" 2.00" 345 Kg 396 Kg
ROUGH-IN-DIMENSIONS
See Models Below
FIGURE 1
MODELS BTR(C) 120 THROUGH 500

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TABLE 1C - HEATER PERFORMANCE DATA BTR MODELS
INPUT APPROX. RECOVERY RATING CAPACITIES (GPH AND LPH)
RATE GAL EFF. 30° F 40° F 50° F 60° F 70° F 80° F 90° F 100° F 110° F 120° F 130° F 140° F
MODEL BTUH CAP. % (-)1° C 4° C 10° C 15° C 21° C 27° C 32° C 38° C 43° C 49° C 54° C 60° C
BTR 120,000 BTUH 71 Gal 80 388 291 233 194 166 145 129 116 106 97 90 83
120 35 Kw/Hr 268 L 1469 1102 882 734 628 549 488 439 401 367 341 314
BTR 154,000 BTUH 81 Gal 80 498 373 299 249 213 187 166 149 136 124 115 107
154 45 Kw/Hr 306 L 1885 1412 1132 943 806 708 628 564 515 469 435 405
BTR 180,000 BTUH 81 Gal 80 579 434 347 289 248 217 193 174 158 145 134 124
180 53 Kw/Hr 306L 2192 1643 1314 1094 939 821 731 659 598 549 507 469
BTR 199,000 BTUH 100 Gal 80 643 482 386 322 276 241 214 193 175 161 148 132
197 58 Kw/Hr 379 L 2434 1825 1461 1219 1045 912 810 731 662 609 560 500
BTR 199,000 BTUH 100 Gal 80 643 482 386 322 276 241 214 193 175 161 148 132
198 58 Kw/Hr 379L 2434 1825 1461 1219 1045 912 810 731 662 609 560 500
BTR 199,000 BTUH 81 Gal 80 614 461 368 307 263 230 205 184 167 154 142 132
199 58 Kw/Hr 306 L 2324 1745 1393 1162 996 871 776 697 632 583 538 500
BTR 199,000 BTUH 100 Gal 80 643 482 386 322 276 241 214 193 175 161 148 132
200 58 Kw/Hr 379 L 2434 1825 1461 1219 1045 912 810 731 662 609 560 500
BTR 250,000 BTUH 100 Gal 80 808 606 485 404 346 303 269 242 220 202 186 173
250 73 Kw/Hr 379 L 3059 2294 1835 1529 1311 1147 1020 918 834 765 706 655
BTR 251,000 BTUH 65 Gal 80 811 608 487 406 348 304 270 243 221 203 187 174
251 73 Kw/Hr 246 L 3071 2303 1843 1536 1316 1152 1024 921 838 768 709 658
BTR 275,000 BTUH 100 Gal 80 889 667 533 444 381 333 296 267 242 222 205 190
275 80 Kw/Hr 379 L 3365 2524 2019 1682 1442 1262 1122 1009 918 841 776 721
BTR 305,000 BTUH 65 Gal 80 986 739 592 493 423 370 329 296 269 246 228 211
305 89 Kw/Hr 246 L 3732 2799 2239 1866 1599 1399 1244 1120 1018 933 861 800
BTR 365,000 85 Gal 80 1180 885 708 590 506 442 393 354 322 295 272 253
365 107 Kw/Hr 322 L 4466 3349 2680 2233 1914 1675 1489 1340 1218 1116 1031 957
BTR 390,000 BTUH 100 Gal 80 1293 970 776 646 554 485 431 388 353 323 298 277
400 114 Kw/Hr 379 L 4894 3671 2936 2447 2097 1835 1631 1468 1335 1224 1129 1049
TABLE 1D - HEATER PERFORMANCE DATA BTR(C) MODELS
INPUT APPROX. RECOVERY RATING CAPACITIES (GPH AND LPH)
RATE GAL EFF. 30° F 40° F 50° F 60° F 70° F 80° F 90° F 100° F 110° F 120° F 130° F 140° F
MODEL BTUH CAP. % (-)1° C 4° C 10° C 15° C 21° C 27° C 32° C 38° C 43° C 49° C 54° C 60° C
BTRC 120,000 BTUH 71 Gal 80 388 291 233 194 166 145 129 116 106 97 90 83
120 35 Kw/Hr 268 L 1469 1102 882 734 628 549 488 439 401 367 341 314
BTRC 154,000 BTUH 81 Gal 80 498 373 299 249 213 187 166 149 136 124 115 107
154 45 Kw/Hr 306 L 1885 1412 1132 943 806 708 628 564 515 469 435 405
BTRC 180,000 BTUH 76 Gal 80 579 434 347 289 248 217 193 174 158 145 134 124
180 53 Kw/Hr 288L 2192 1643 1314 1094 939 821 731 659 598 549 507 469
BTRC 199,000 BTUH 95 Gal 80 643 482 386 322 276 241 214 193 175 161 148 132
197 58 Kw/Hr 360 L 2434 1825 1461 1219 1045 912 810 731 662 609 560 500
BTRC 199,000 BTUH 76 Gal 80 614 461 368 307 263 230 205 184 167 154 142 132
199 58 Kw/Hr 288 L 2324 1745 1393 1162 996 871 776 697 632 583 538 500
BTRC 199,000 BTUH 100 Gal 80 643 482 386 322 276 241 214 193 175 161 148 132
200 58 Kw/Hr 379 L 2434 1825 1461 1219 1045 912 810 731 662 609 560 500
BTRC 250,000 BTUH 100 Gal 80 808 606 485 404 346 303 269 242 220 202 186 173
250 73 Kw/Hr 379 L 3059 2294 1835 1529 1311 1147 1020 918 834 765 706 655
BTRC 251,000 BTUH 65 Gal 80 811 608 487 406 348 304 270 243 221 203 187 174
251 73 Kw/Hr 246 L 3071 2303 1843 1536 1316 1152 1024 921 838 768 709 658
BTRC 275,000 BTUH 100 Gal 80 889 667 533 444 381 333 296 267 242 222 205 190
275 80 Kw/Hr 379 L 3365 2524 2019 1682 1442 1262 1122 1009 918 841 776 721
BTRC 305,000 BTUH 65 Gal 80 986 739 592 493 423 370 329 296 269 246 228 211
305 89 Kw/Hr 246 L 3732 2799 2239 1866 1599 1399 1244 1120 1018 933 861 800
BTRC 360,000 BTUH 65 Gal 80 1164 873 698 582 499 436 388 349 317 291 269 249
365 105 Kw/Hr 246 L 4405 3304 2643 2202 1888 1652 1468 1321 1201 1101 1016 944
BTRC 390,000 BTUH 100 Gal 80 1293 970 776 646 554 485 431 388 353 323 298 277
400 114 Kw/Hr 379 L 4894 3671 2936 2447 2097 1835 1631 1468 1335 1224 1129 1049

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TABLE OF CONTENTS
ROUGH-IN-DIMENSIONS ---------------------------------------- 2-3
TABLE OF CONTENTS---------------------------------------------- 4
FOREWORD ----------------------------------------------------------- 4
GENERAL SAFETY INFORMATION ----------------------------- 5
Chemical Vapor Corrosion ------------------------------------------ 5
Improper Combustion ------------------------------------------------ 5
Liquid Petroleum Models -------------------------------------------- 5
Extended Non-Use Periods----------------------------------------- 5
Insulation Blankets -------------------------------------------------- 5-6
High Altitude Installation --------------------------------------------- 6
FEATURES ------------------------------------------------------------- 6
The Eliminator (Self-Cleaning System) -------------------------- 6
High Limit Switch (E.C.O.) ----------------------------------------6-7
Electronic Ignition Control ------------------------------------------- 7
Automatic Flue Damper Device ----------------------------------- 7
Circulating Pump ------------------------------------------------------ 7
Dishwashing Machine Requirement ---------------------------- 7-8
INSTALLATION INSTRUCTIONS --------------------------------- 8
Uncrating ---------------------------------------------------------------- 8
Locating The Heater -------------------------------------------------- 8
Levelling ----------------------------------------------------------------- 8
Clearances ------------------------------------------------------------ 8-9
Installation on Combustible Flooring ----------------------------- 9
Hard Water-------------------------------------------------------------- 9
Air Requirements -------------------------------------------------- 9-10
Unconfined Space --------------------------------------------------- 9
Confined Space ----------------------------------------------------- 10
Vent Reducer ----------------------------------------------------------10
Venting ------------------------------------------------------------------10
Multiple Heater Manifold --------------------------------------------10
Water Line Connections --------------------------------------------10
Technical Data Venting------------------------------------------11-12
Water (Potable) Heating and Space Heating -----------------13
Thermometers (Not Supplied) ------------------------------------13
Relief Valve ------------------------------------------------------------13
Gas Piping -------------------------------------------------------- 13-14
Gas piping and Dirt Leg Installation ------------------------ 14-15
Gas Pressure Regulator --------------------------------------------15
Grounding Instructions---------------------------------------------- 15
Heater Wiring---------------------------------------------------------- 15
INSTALLATION DIAGRAMS---------------------------------- 15-21
MANIFOLDS ----------------------------------------------------------- 22
MECHANICALVENTING------------------------------------------- 23
Single Unit Installation ---------------------------------------------- 23
Vent Installation ------------------------------------------------------- 23
Multiple Unit Installation --------------------------------------------23
OPERATION ----------------------------------------------------------- 24
General ----------------------------------------------------------------- 24
Filling -------------------------------------------------------------------- 24
Purging ------------------------------------------------------------------ 24
Lighting and Operating Labels ------------------------------- 25-26
Water Temperature Control ---------------------------------------- 27
Testing Damper Control--------------------------------------------- 27
Checking Venting------------------------------------------------ 27-28
PREVENTIVE MAINTENANCE----------------------------------- 28
Check The Pilot ------------------------------------------------------- 28
Pilot Burner ------------------------------------------------------------ 28
Main Burner------------------------------------------------------- 28-29
Gas Valves ------------------------------------------------------------- 29
Checking The Input -------------------------------------------------- 29
Venting System ------------------------------------------------------- 30
Remote Storage Tank Temperature Control -------------------30
Relief Valve ------------------------------------------------------------ 30
Hot Water Odor ------------------------------------------------------- 30
Anode Rod Inspection ----------------------------------------------30
Recommended Procedure For Periodic Removal
of Lime Deposits From Tank Type Commercial
Water Heaters ---------------------------------------------------- 30-31
Deliming Solvents ---------------------------------------------------- 31
Tank Cleanout Procedures------------------------------------ 31-32
Troubleshooting Ignition Module System ---------------------- 32
SERVICE --------------------------------------------------------------- 32
Electrical Servicing --------------------------------------------------- 32
Replacement Parts--------------------------------------------------- 32
Effikal Flue Damper Troubleshooting Guide ------------------ 33
Operational Checklist ----------------------------------------------- 34
Limited Warranty ----------------------------------------------------- 35
Page Page
FOREWORD
These designs comply with ANSI Z21.10.3/CSA 4.3 as an
automaticcirculating or automatic storage tanktypewater heater.
Heatershaving an inputof 305,000 (89Kwh), 365,000 (107 Kwh),
399,000 (117 Kwh) and 500,000 (147 Kwh) Btuh with a recovery
rating of 277.3 gph (1049 Lph) or more also comply with ANSI
Z21.10.3 as an automatic instantaneous type heater.
Detailed installation diagrams are found in this manual. These
diagrams will serve to provide the installer with a reference for
the materials and methods of piping necessary. It is highly
essentialthatallwater,gas piping and wiring beinstalledasshown
on the diagrams.
Particular attention should be given to the installation of
thermometers at the locations indicated on the diagrams as
these are necessary for checking the proper functioning of the
heater.
This model water heater is designed and manufactured in both
naturalgas and propaneversions.MAKESURE the gason which
the heater will operate is the same as that specified on the heater
model and rating plate.
These heaters may be installed on combustible floors.
In addition to these instructions, the equipment shall be installed
in accordance with those installation regulations in force in the
local area where the installation is to be made. These shall be
carefully followed in all cases. Authorities having jurisdiction
should be consulted before installations are made.
The installation must conform to these instructions and the local
code authority having jurisdiction. In the absence of local codes,
theinstallationmustcomply with the latest editions of theNational
FuelGas Code,ANSI Z223.1/NFPA54 and theNational Electrical
Code, NFPA70 or CAN/CSA B149.1-00, and CSA 2 C22.1. The
formerisavailablefromtheCanadianStandardsAssociation, 8501
East Pleasant Valley Road, Cleveland, OH 44131, and both
documents are available from the National Fire Protection
Association, 1 Batterymarch Park, Quincy, MA 02269.

5
GENERAL SAFETY
INFORMATION
PRECAUTIONS
DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN
UNDER WATER. Immediately call a qualified service technician
to inspect the appliance and to replace any part of the control
system and any gas control which has been under water.
IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT
OPERATE HEATER UNTIL ALL CORRECTIVE STEPS HAVE
BEEN MADE BYAQUALIFIED SERVICEMAN.
1. EXTERNALFIRE.
2. DAMAGE.
3. FIRING WITHOUT WATER.
4. SOOTING
CHEMICAL VAPOR CORROSION
WARNING
CORROSION OF THE FLUEWAYS AND VENT SYSTEM MAY
OCCUR IF AIR FOR COMBUSTION CONTAINS CERTAIN
CHEMICAL VAPORS. SUCH CORROSION MAY RESULT IN
FAILURE AND RISK OF ASPHYXIATION.
Spray can propellants, cleaning solvents, refrigerator and air
conditioning refrigerants, swimming pool chemicals, calcium
and sodium chloride (water softener salt), waxes, and process
chemicals are typical compounds which are potentially
corrosive. Do not store products of this sort near the heater.
Also, air which is brought in contact with a the heater should
not contain any of these chemicals. If necessary,
uncontaminated air should be obtained from remote or outside
sources. The limited warranty is voided when failure of water
heater is due to a corrosive atmosphere. (Refer to the limited
warranty for complete terms and conditions.)
IMPROPER COMBUSTION
WARNING
ATTIC AND/OR EXHAUST FANS OPERATING ON THE
PREMISESWITHAWATER HEATER CAN RESULTIN CARBON
MONOXIDE POISONINGAND DEATH.
OPERATION OF THESE FANS CAN PRODUCE A NEGATIVE
DRAFT IN THEAREAOF THE WATER HEATER PREVENTING
THE PRODUCTS OF COMBUSTION FROM EXHAUSTING
THROUGH THE CHIMNEY OR VENTPIPE.
Theventing of thewater heater shouldbe inspected by aqualified
service technician at the time of installation and periodically
thereafter to ensure a down-draft condition does not exist.
DO NOT OBSTRUCT THE FLOW OF COMBUSTION AND
VENTILATING AIR. ADEQUATE AIR FOR COMBUSTION AND
VENTILATION MUST BE PROVIDED FOR SAFE OPERATION.
LIQUID PETROLEUM MODELS
Water heaters for propane or liquefied petroleum gas (LPG) are
different from natural gas models. A natural gas heater will not
function safely on LP gas and no attempt should be made to
convert a heater from natural gas to LP gas.
LP gas must be used with great caution. It is highly explosive
and heavier than air. It collects first in the low areas making its
odor difficult to detect at nose level. If LP gas is present or even
suspected, do not attempt to find the cause yourself. Go to a
neighbor'shouse, leavingyour doors open to ventilate the house,
then call your gas supplier or service agent. Keep area clear
until a service call has been made.
At times you may not be able to smell an LP gas leak. One
cause is odor fade, which is a loss of the chemical odorant that
gives LP gas its distinctive smell. Another cause can be your
physical condition, such as having a cold or diminishing sense of
smell with age. For these reasons, the use of a propane gas
detector is recommended.
IF YOU EXPERIENCE AN OUT-OF-GAS SITUATION, DO NOT
TRY TO RELIGHT APPLIANCES YOURSELF, Ask your LP
delivery person to relight pilots for you. Only trained LP
professionals should conduct the required safety checks in
accordance with industry standards.
EXTENDED NON-USE PERIODS
WARNING
HYDROGEN GAS CAN BE PRODUCED IN A HOT WATER
SYSTEM SERVED BY THIS HEATER THAT HAS NOT BEEN
USED FOR A LONG PERIOD OF TIME (GENERALLY TWO
WEEKS OR MORE). HYDROGEN GAS IS EXTREMELY
FLAMMABLE. To reduce therisk of injury underthese conditions,
itis recommended thatthe hot water faucetbe opened forseveral
minutes at the kitchen sink before using any electrical appliance
connected to the hot water system. If hydrogen is present, there
will probably be an unusual sound such as air escaping through
the pipe as the water begins to flow. THERE SHOULD BE NO
SMOKINGOR OPEN FLAME NEARTHEFAUCETATTHE TIME
IT IS OPEN.
INSULATION BLANKETS
Insulation blankets available to the general public for external
use on gas water heaters are not approved for use on your A.O.
Smith water heater. The purpose of an insulation blanket is to
reducethe standbyheatloss encountered withstoragetankwater
heaters. Your A.O. Smith water heater meets or exceeds the
ANSI/ASHRAE/IESNA Standard 90.1 1999 with respect to
insulation and standby loss requirement making an insulation
blanket unnecessary.
WARNING
Should you choose to apply an insulation blanket to this heater,
you should follow these instructions. Failure to follow these
instructionscanresultin fire, asphyxiation ,seriouspersonalinjury
or death.
•Do not apply insulation to the top of the water heater, as this
will interfere with safe operation of drafthood.
•Do not cover the gas valve or temperature & pressure relief
valve.

6
•Do not cover the instruction manual. Keep it on the side of the
water heater or nearby for future reference.
•Do not allow insulation to come within 2” (5 cm) of the burners,
to prevent blockage of combustion air flow to the burners.
•Donot allow insulation tocomewithin9” (23 cm) offloor, (within
2” (5 cm) of bottom cover) to prevent blockage of combustion
air flow to the burners.
•Do inspect the insulation blanket frequently to make sure it
does not sag, thereby obstructing combustion air flow.
•Do obtain new labels from A.O. Smith for placement on the
blanket directly over the existing labels.
HIGHALTITUDE INSTALLATIONS
WARNING
INSTALLATIONSABOVE 2000 FEET (610 METERS) REQUIRE
REPLACEMENTOFTHEBURNERORIFICESINACCORDANCE
WITH THE NATIONAL FUEL GAS CODE (ANSI Z223.1). FOR
CANADIAN INSTALLATIONS CONSULT NATURAL GAS AND
PROPANE INSTALLATION CODE CAN/CSA-B149.1. FAILURE
TOREPLACETHE ORIFICES WILLRESULTINIMPROPERAND
INEFFICIENT OPERATION OF THE APPLIANCE RESULTING
IN THE PRODUCTION OF INCREASED LEVELS OF CARBON
MONOXIDEGAS IN EXCESSOF SAFE LIMITS WHICHCOULD
RESULT IN SERIOUS PERSONALINJURY OR DEATH.
You should contact your gas supplier for any specific changes
which may be required in your area.
As elevation above sea level is increased, there is less oxygen
per cubic foot of air. Therefore, the heater input rate should be
reducedathighaltitudesforsatisfactoryoperationwiththereduced
oxygen supply. Failure to make this reduction would result in an
overfiring of the heater causing sooting, poor combustion and/or
unsatisfactory heater performance.
U.S. REQUIREMENTS
Ratings specified by manufacturers for most appliances apply
for elevations up to 2000 feet (610 m). For elevations above
2000 feet (610), ratings must be reduced at the rate of 4% for
each 1000 feet (305 m) above sea level. For example, if a heater
is rated at 120,000 Btuh (35 Kwh) at sea level, to rate the heater
at 4000 feet (1219 m), you subtract 4 (once for each thousand
feet) x 04 (4% input reduction) x 120,000 (original rating) from
the original rating. Therefore, to calculate the input rating at
4,000 feet (121.9 m): 4 x .04 x 120,000 =19,200 Btuh (5.6 Kwh),
120,000 (35 Kwh) - 19,200 (5.6 Kwh) = 100,800 Btuh (29.4 Kwh).
At 6000 feet (1829 m) the correct input rating should be 91,200
Btuh (26.7 Kwh).
CANADIAN REQUIREMENTS
Appliances with inputs up to and including 400,000 BTU (117.2
Kw)mustbe factory equipped withorificesfor operation at specific
elevations. Standard (sea level) orifices permit operation up to
2000' (610 m) elevation. For operation between 2000' (610 m)
and4500'(1370m) specify "HIGHALTITUDEOPERATION"when
ordering the heater(s). For operation above 4500' (2370 m)
consult factory before ordering.
Field conversion for operation at altitudes other than
thatspecified on the heater rating plate is not permitted.
The input reduction is primarily achieved by reducing the size of
themainburnerorifices. Todothis,themainburnerorificesrequire
replacement with orifices sized for the particular installation
elevation. Correct orifice sizing and parts may be obtained from
A.O. Smith Water Products Company. When ordering, be sure
to state the model number and the altitude of the location where
the water heater is being installed.
Upon completion of derating of the heater, adjustment to the gas
pressureregulatormay be required. See CHECKINGTHEINPUT
section in this manual for inlet and manifold pressure
requirements.
Also due to the input rating reduction required at high altitudes,
the output rating of the appliance is reduced and should be
compensated for in the sizing of the equipment for application.
FEATURES
THE ELIMINATOR
(SELF-CLEANING SYSTEM)
These units include The Eliminator (Self-Cleaning System)
installed in the front water inlet. See figure 2. The Eliminator
must be oriented correctly for proper function. There is a marked
range on the pipe nipple portion of the Eliminator, that must be
aligned with the top of the inlet spud. A label above the jacket
hole has an arrow that will point to the marked portion of the pipe
nippleif the orientationis correct. Ifthe arrow does notpoint within
the marked range on the pipe nipple, adjust the pipe nipple to
correct. A pipe union is supplied with the Eliminator to reduce the
probability of misaligning the Eliminator accidentally while
tightening the connection to the inlet water supply line. Improper
orientation of the Eliminator can cause poor performance of the
heater and can significantly reduce outlet water temperatures
during heavy draws.
NOTE: The inlet tube may have 1, 3 or 7 cross-tubes.
FIGURE 2
For proper function, The Eliminator must be oriented correctly.
There is a marked range on the pipe nipple that must be aligned
with the top of the inlet spud (check for label on the appliance) to
assureproperorientation.Pleasechecktoconfirmthatthemarked
range is in alignment with the top of the spud. A pipe union is
supplied with The Eliminator to help eliminate the possibility of
changing the orientation by accidentally over-tightening the inlet
supply line. Improper orientation of The Eliminator may cause
temperature build-up issues or spells of colder than usual water
temperatures.
HIGH LIMIT SWITCH
Thedigital thermostat(Fig. 3)containsthehighlimit(energycutoff)
sensor.Thehighlimitswitchinterrupts main burner gas flow should
the water temperature reach 203°F (95°C).
In the event of high limit switch operation, the appliance cannot
be restarted unless the water temperature is reduced to
approximately 120°F (49°C). The high limit reset button on the
front of the control then needs to be depressed.

7
Continued manual resetting of high limit control, preceded by higher
thanusualwatertemperatureisevidenceofhighlimitswitchoperation.
The following is a possible reason for high limit switch operation:
• A malfunction in the thermostatic controls would allow the gas
valve to remain open causing water temperature to exceed
the thermostat setting. The water temperature would continue
to rise until high limit switch operation.
Contact your dealer or service agent if continued high limit switch
operation occurs.
DIGITAL THERMOSTAT
FIGURE 3
ELECTRONIC IGNITION CONTROL
Each heater is equipped with a Honeywell ignition module. The
solid state ignition control, fig.4, ignites the pilot burner gas by
creating a spark at the pilot assembly. Pilot gas is ignited and
burnsduring each running cycle. Themain burner and pilotgases
are cut off during the OFF cycle. Pilot gas ignition is proven by
the pilot sensor. Main burner ignition will not occur if the pilot
sensor does not first sense pilot ignition.
HONEYWELL IGNITION MODULE
S8600M Continuous Re-Try
FIGURE 4
AUTOMATIC FLUE DAMPER DEVICE
All units are equipped with an automatic flue damper that
reduces heat loss during the OFF cycles. The automatic flue
damper drive assembly is a field replaceable part and may be
obtained by contacting A. O. Smith Water Products Company
at 500 Tennessee Waltz Parkway, Ashland City, TN 37015,
1-800-433-2545. In Canada, contact A.O. Smith Enterprises
LTD., P.O. Box, 310 - 768 Erie Street, Stratford, Ontario, Canada
N5A 6T3, 1-800-265-8520.
Each automatic flue damper drive assembly is equipped with a
“Service Switch”, as shown in figure 5.
FIGURE 5
The “Service Switch” has 2 positions: AUTOMATIC
OPERATION and HOLD OPEN DAMPER. For normal
operation the switch should be in the AUTOMATIC
OPERATION position.
If there is a problem with the damper the “Service Switch”
can be placed in the HOLD OPEN DAMPER position. When
the switch is placed in the HOLD OPEN DAMPER position
the damper disc will rotate to the open position and the
heater may be used until vent assembly is repaired or
replaced. DO NOT turn the damper disc manually; damage
will occur to the drive assembly if operated manually. Refer
to TESTING DAMPER OPERATION section of this manual
for additional information.
CIRCULATING PUMP
A circulating pump is used when a system requires a circulating
loop or there is a storage tank used in conjunction with the heater.
Refer to the piping diagrams in this manual for electrical hookup
information and install in accordance with the current edition of
the National Electrical Code NFPA 70. For Canada refer to the
Canadian Electrical Code CSA C22.1.
Only all bronze circulators should be used with commercial water
heaters.
Although circulators are oiled and operated by the manufacturer
some circulators must be oiled again before operating. Please
refer to manufacturer’s instructions.
DISHWASHING MACHINE REQUIREMENT
These appliances meet the NSF Standard 5 for sanitary
installations when used with the following leg kits, Part No’s.
6570-0 and 6570-7.
All dishwashing machines meeting the National Sanitation
Foundation requirements are designed to operate with water flow
pressures between 15 and 25 psi (103 kPa and 173 kPa). Flow
pressures above 25 psi (173 kPa), or below 15 psi (103 kPa), will
result in improperly sanitized dishes. Where pressures are high,
a water pressure reducing or flow regulating control valve should
be used in 180°F (82°C) line to the dishwashing machine, and
should be adjusted to deliver water between these limits.

8
NEVERBEPLACEDONORADJACENTTOTHEHEATER. OPEN
CONTAINERS OR FLAMMABLE MATERIAL SHOULD NOT BE
STORED OR USED IN THE SAME ROOM WITH THE HEATER.
THE HEATER MUST NOT BE LOCATED IN AN AREA WHERE
IT WILL BE SUBJECT TO FREEZING.
LOCATE IT NEAR A FLOOR DRAIN. THE HEATER SHOULD
BE LOCATED IN AN AREA WHERE LEAKAGE FROM THE
HEATER OR CONNECTIONS WILLNOT RESULT IN DAMAGE
TO THE ADJACENT AREA OR TO LOWER FLOORS OF THE
STRUCTURE.
WHENSUCHLOCATIONSCANNOTBEAVOIDED,ASUITABLE
DRAIN PAN SHOULD BE INSTALLED UNDER THE HEATER.
Suchpansshouldbe fabricated with sides at least 2"(5 cm) deep,
with length and width at least 2" (5 cm) greater than the diameter
of the heater and must be piped to an adequate drain. The pan
must not restrict combustion air flow.
For appliance installation locations with elevations above 2000
feet (610 m), refer to HIGH ALTITUDE INSTALLATIONS section
of this manual for input reduction procedure.
LEVELING
If the unit is not level, insert the bolts which were used in crating
into the legs to correct this condition.
CLEARANCES
These heaters are approved for installation on combustible
flooring in an alcove when the minimum clearance from any
combustion construction are followed as indicated in figure 6
and Table 2.
The following units are approved for installation with side, rear
and ceiling clearances as indicated below:
ABC D
(RIGHT SIDE) (LEFT SIDE) (BACK) (CEILING)
120 1” (2.54 cm) 1” (2.54 cm) 1” (2.54 cm) 12” (30.48 cm)
154 1” (2.54 cm) 1” (2.54 cm) 1” (2.54 cm) 12” (30.48 cm)
*180 1” (2.54 cm) 1” (2.54 cm) 1” (2.54 cm) 12” (30.48 cm)
*197 1” (2.54 cm) 1” (2.54 cm) 1” (2.54 cm) 12” (30.48 cm)
198 1” (2.54 cm) 1” (2.54 cm) 1” (2.54 cm) 12” (30.48 cm)
*199 1” (2.54 cm) 1” (2.54 cm) 1” (2.54 cm) 12” (30.48 cm)
200 1” (2.54 cm) 1” (2.54 cm) 1” (2.54 cm) 12” (30.48 cm)
250 2” (5.08 cm) 2” (5.08 cm) 2” (5.08 cm) 12” (30.48 cm)
251 2” (5.08 cm) 2” (5.08 cm) 2” (5.08 cm) 12” (30.48 cm)
275 2” (5.08 cm) 2” (5.08 cm) 2” (5.08 cm) 12” (30.48 cm)
305 2” (5.08 cm) 2” (5.08 cm) 2” (5.08 cm) 12” (30.48 cm)
**365 3” (7.75 cm) 3” (7.75 cm) 3” (7.75 cm) 12” (30.48 cm)
400 3” (7.75 cm) 3” (7.75 cm) 3” (7.75 cm) 12” (30.48 cm)
* The BTRC version has a 2” (5.08cm) to sides and rear.
** The BTRC version has a 4” (10.16cm) to sides and rear.
TABLE 2
In all installations the minimum combustible clearances from any
draft hood surface or vent piping shall be 6" (16cm). Vent piping
passingthroughacombustiblewallorceilingmustbe a continuous
run (no joints) and retain the 6" (16cm) clearance unless an
approved reducing thimble is used.
The National Sanitation Foundation also recommends circulation
of 180°F (82°C) water. Where this is done, the circulation should
be very gentle so that it does not cause any unnecessary
turbulence inside the water heater. The circulation should be just
enough to provide 180°F (82°C) water at the point of take-off to
the dishwashing machine. Adjust flow by means of the plug cock
in the circulating line.
INSTALLATION INSTRUCTIONS
REQUIREDABILITY
INSTALLATION OR SERVICE OF THIS WATER HEATER
REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED
TRADESMAN IN THE FIELD INVOLVED. PLUMBING, AIR
SUPPLY, VENTING, GAS SUPPLY AND ELECTRICAL WORK
ARE REQUIRED.
WARNING
FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT
IN SERIOUS PERSONALINJURY OR DEATH.
UNCRATING
The heater is shipped with the flue damper already installed. The
wiringconduit runs fromthe thermostat to thedamper drive cover.
Before turning unit on, check to make sure the wiring conduit is
securely plugged into damper drive.
LOCATING THE HEATER
When installing the heater, consideration must be given to proper
location. Location selected should be as close to the stack or
chimney as practicable, with adequate air supply and as
centralized with the piping system as possible.
WARNING
THERE IS A RISK IN USING FUEL BURNING APPLIANCES
SUCH AS GAS WATER HEATERS IN ROOMS, GARAGES OR
OTHER AREAS WHERE GASOLINE, OTHER FLAMMABLE
LIQUIDSORENGINEDRIVENEQUIPMENTOR VEHICLESARE
STORED, OPERATED OR REPAIRED. FLAMMABLE VAPORS
ARE HEAVY AND TRAVELALONG THE FLOOR AND MAY BE
IGNITEDBYTHE HEATER’S PILOTOR MAIN BURNER FLAMES
CAUSING FIRE OR EXPLOSION. SOME LOCAL CODES
PERMIT OPERATION OF GASAPPLIANCES IN SUCH AREAS
IF THEYARE INSTALLED 18” (.50 m). OR MORE ABOVE THE
FLOOR. THISMAYREDUCETHERISKIF LOCATION IN SUCH
AN AREA CANNOT BEAVOIDED.
DO NOT INSTALL THIS WATER HEATER DIRECTLY ON A
CARPETED FLOOR. A FIRE HAZARD MAY RESULT. Instead
the water heater must be placed on a metal or wood panel
extending beyond the full width and depth by at least 3 inches
(7.6 cm) in any direction. If the heater is installed in a carpeted
alcove, the entire floor shall be covered by the panel. Also, see
the DRAIN REQUIREMENTS.
THE HEATER SHALL BE LOCATED OR PROTECTED SO IT IS
NOTSUBJECTTOPHYSICALDAMAGEBYAMOVINGVEHICLE.
WARNING
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST

9
Aservice clearance of 24" (61cm) should be maintained from
serviceable parts, such as relief valves, flue baffles, flue
damper devices, thermostats, cleanout openings or drain
valves.
HARD WATER
Where hard water conditions exist, water softening or the
threshold type of water treatment is recommended. This will
protect the dishwashers, coffee urns, water heaters, water piping
and other equipment.
SeeMAINTENANCEsectionfordetailsof tankcleanoutprocedure.
AIR REQUIREMENTS
REFERTOTHE CURRENTEDITIONOFTHE "NATIONALFUEL
GAS CODE" ANSI Z223.1/NFPA 54. FOR CANADA CONSULT
NATURAL GAS AND PROPANE INSTALLATION CODE
CAN/CSA-B149.1.
WARNING
KEEPAPPLIANCEAREACLEARANDFREEOFCOMBUSTIBLE
MATERIALS,GASOLINEANDOTHERFLAMMABLES, VAPORS
AND LIQUIDS.
DO NOT OBSTRUCT THE FLOW OF COMBUSTION OR
VENTILATINGAIR.
WARNING
FOR SAFE OPERATION PROVIDE ADEQUATE AIR FOR
COMBUSTIONANDVENTILATION. ANINSUFFICIENTSUPPLYOF
AIRWILLCAUSERECIRCULATIONOFCOMBUSTIONPRODUCTS
RESULTING INAIRCONTAMINATIONTHATMAY BE HAZARDOUS
TOLIFE. SUCHACONDITIONOFTENWILLRESULTINAYELLOW,
LUMINOUSBURNERFLAME,CAUSINGCARBONINGORSOOTING
OFTHE COMBUSTION CHAMBER, BURNERS AND FLUE TUBES
AND CREATESARISK OF ASPHYXIATION.
Where an exhaust fan is supplied in the same room with a heater,
sufficient openings for air must be provided in the walls.
UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN
INTO THE ROOMTHROUGH THE CHIMNEY, CAUSING POOR
COMBUSTION. SOOTINGMAYRESULTINSERIOUS DAMAGE
TOTHE HEATERAND RISK OF FIRE OR EXPLOSION.
UNCONFINED SPACE
In buildings of conventional frame, brick, or stone construction,
unconfined spaces may provide adequate air for combustion,
ventilation and draft hood dilution.
If the unconfined space is within a building of tight construction
(buildingsusingthefollowingconstruction:weatherstripping, heavy
insulation, caulking, vapor barrier, etc.), air for combustion,
ventilation and draft hood dilution must be obtained from outdoors.
Theinstallation instructionsforconfinedspacesintightlyconstructed
buildings must be followed to ensure adequate air supply.
ILLUSTRATION OF MINIMUM COMBUSTIBLE CLEARANCES IN AN ALCOVE
FIGURE 6

10
CONFINED SPACE
When drawing combustion and dilution air from inside a
conventionally constructed building to a confined space, such a
space shall be provided with two permanent openings, ONE IN
OR WITHIN 12 INCHES (30.5cm) OF THE ENCLOSURE TOP
AND ONE IN OR WITHIN 12 INCHES (30.5cm) OF THE
ENCLOSURE BOTTOM. Each opening shall have a free area of
at least one square inch per 1000 Btuh (2,225mm2/Kw) of the
total input of all appliances in the enclosure, but not less than 100
square inches (645 square cm).
If the confined space is within a building of tight construction, air
for combustion, ventilation, and draft hood dilution must be
obtained from outdoors. When directly communicating with the
outdoors or communicating with the outdoors through vertical
ducts, two permanent openings, located in the above manner,
shall be provided. Each opening shall have a free area of not
less than one square inch per 4000 Btuh (8,900mm2/Kw) of the
total input of all appliances in the enclosure. If horizontal ducts
are used, each opening shall have a free area of not less than
one square inch per 2000 Btuh (4,450mm2/Kw) of the total input
of all appliances in the enclosure. For Canadian installations
consult CAN/CSA B149.1-00.
VENT REDUCER
The BTR(C) 250, 251, and 275 models are shipped with an 8" to 6"
diameterflueoutletadapter.Eachadapterfitsontopoftheinstalled
flue damper. Use only vent reducers supplied with the unit. The
venting must comply with the NATIONALFUELGAS CODE,ANSI
Z223.1/NFPA54 and for Canadian installations consult the Natural
Gas and Propane Installation Code CAN/CSA-B149.1.
FIGURE 8
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING MUST
BE FOLLOWED TO AVOID CHOKED COMBUSTION OR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS
CAUSE SOOTING OR RISKS OF FIRE AND ASPHYXIATION.
Heater must be protected from freezing downdrafts.
Remove all soot or other obstructions from the chimney that will
retard a free draft.
Type B venting is recommended with these heaters. See table 3
TECHNICAL DATA VENTING.
This water heater must be vented in compliance with all local
codes, the current edition of the National Fuel Gas Code (ANSI-
Z223.1) and with the Category I Venting Tables.
InCanada,ventingshallconformtotherequirementsofthecurrent
Natural Gas and Propane Installation Code CAN/CSA-B149.1
installation code.
If any parts of the vent system are exposed to ambient
temperatures below 35 degrees F (2 degrees C) they must be
insulated to prevent condensation.
• Do not connect the heater to a common vent or chimney with
solid fuel burning equipment. This practice is prohibited by
many local building codes as is the practice of venting gas
fired equipment to the duct work of ventilation systems.
• Where a separate vent connection is not available and the vent
pipe from the heater must be connected to a common vent with
an oil burning furnace, the vent pipe should enter the smaller
common vent or chimney at a point above the large vent pipe.
FIGURE 9
MULTIPLE HEATER MANIFOLD
Figure 10 and table 3 should be used for horizontally manifolding
twoormore heaters. Also seeMULTIPLE-UNITINSTALLATIONS
ofMECHANICALVENTING section for induceddraftapplications.
FIGURE 10
WATER LINE CONNECTIONS
This manual provides detailed installation diagrams (see pages
16-22 of this manual) for typical methods of application for the
water heaters.
The water heater may be installed by itself, or with a separate
storage tank, on both single and two-temperature systems.
When used with a separate storage tank, the circulation may be
either by gravity or by means of a circulating pump. When a
circulating pump is used it is important to note that the flow rate
should be slow so that there will be a minimum of turbulence
inside the heater.

11
MODEL BTR(C)-120
Input: 120,00Btuh Total Vent Height (Feet)
Draft Hood: 5” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (inches)
120,000 1 Ft. 7 7 7 6 6 6 6 6
120,000 2 Ft. 6 6 6 6 6 6 6 5
123,000 3 Ft. 6 6 6 6 6 5 5 5
Number Combined Input
of Heaters in Thousands of Btuh Manifold and Common Vent Diameter (In inches)
2 240 108877767
3 360 10 10 10 10 8 8 7 7
4 480 12 12 12 10 10 10 8 8
MODEL BTR(C)-154
Input: 154,000 Btuh Total Vent Height (Feet)
Draft Hood: 6” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (in inches)
154,000 1 Ft. 8 8 7 7 7 7 7 7
154,000 2 Ft. 7 7 7 7 7 6 6 6
154,000 3 Ft. 7 7 7 6 6 6 6 6
Numbers Combined Input
of Heaters in Thousands of Btuh Manifold and Common Vent Diameter (in inches)
2 308 10 10 10 8 8 7 7 7
3 462 12 12 12 10 10 10 8 8
4 618 14 14 12 12 12 10 10 10
MODEL BTR(C)-180, 197, 198, 199, 200
Input: 180,000, 190,000, 199,000 Btuh Total Vent Height (Feet)
Draft Hood: 6” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (in inches)
180,000 1 Ft. 8 8 8 8 8 7 7 7
190,000 - 8 8 8 8 8 7 7
199,000 - - 8 8 8 8 8 7
180,000 2 Ft. 8 8 7 7 7 7 7 7
190,000 8 8 8 7 7 7 7 7
199,000 8 8 8 8 7 7 7 7
179,000 3 Ft. 7 7 7 7 7 7 6 6
190,000 8 7 7 7 7 7 6 6
197,000 8 7 7 7 7 7 7 6
199,000 8 8 7 7 7 7 7 6
Number of Combined Input
Heaters in Thousands of Btuh Manifold & Common Vent Diameter
358 10 10 10 10 8 8 7 7
2 380 12 10 10 10 10 8 7 7
394/398 12 10 10 10 10 8 8 7
537 14 12 12 12 10 10 10 8
3 570 14 12 12 12 10 10 10 10
591/597 14 14 12 12 12 10 10 10
716 14 14 14 12 12 12 10 10
4 760 16 14 14 14 12 12 10 10
788/796 16 14 14 14 12 12 12 10
TYPE B GAS VENT
Multiple Gas Fired Tank-Type Heaters
When venting mutiple tank type heaters using Type B
vent pipe, follow the installation diagram (figure 8) and
tables below which give sizing and data based upon
NFPA 54/ANSI Z223.
TECHNICAL DATA VENTING, TABLE 3

12
MODEL BTR(C)-250, 251
Input: 250,000, 251,000 Total Vent Height (Feet)
Draft Hood: 6” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (in inches)
250/251,000 1 Ft. - - - - - - 8 8
250/251,000 - - - 8 8 8 8 8
250/251,000 3 Ft. - 8 8 8 - 8 7 7
Number Combined Input
of Heaters in Thousands of Btuh Manifold and Common Vent Diameter (In inches)
2 480 14 12 12 10 10 10 8 8
500/502 14 12 12 10 10 10 10 8
3 720 14 14 14 12 12 12 10 10
750/753 16 14 14 14 12 12 10 10
4 960/1000/1004 18 16 16 14 14 14 12 12
MODEL BTR(C)-275
Input: 275,000 Btuh Total Vent Height (Feet)
Draft Hood: 6” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (in inches)
275,000 2 Ft. - - - - - 8 8 8
275,000 3 Ft. - - - 8 8 8 8 8
Numbers Combined Input
of Heaters in Thousands of Btuh Manifold and Common Vent Diameter (in inches)
2 550 - - - 1210101010
3 825 - - - 1414121212
4 1100 - - - 1614141212
MODEL BTR(C)-305
Input: 305,000 Btuh Total Vent Height (Feet)
Draft Hood: 8” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (in inches)
315,000 1 Ft. - - 10 10 10 10 10 10
305,000 2 Ft. 10 10 10 10 10 10 8 8
365,000 3 Ft. 10 10 10 10 10 8 8 8
Number of Combined Input
Heaters in Thousands of Btuh Manifold & Common Vent Diameter
2 610 14 14 12 12 12 10 10 10
3 915 16 16 16 14 14 12 12 12
4 1220 18 18 16 16 16 14 14 12
MODEL BTR(C)-365, 400
Input: 365,000, 399,000 Total Vent Height (Feet)
Draft Hood: 8” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (in inches)
365,000 1 Ft. - - - - - 10 10 10
400,000 - - - - - - 10 10
365,000 2 FT. 12 12 10 10 10 10 10 10
400,000 12 12 12 12 10 10 10 10
365,000 3 FT. 10 10 10 10 10 10 10 10
400,000 12 10 10 10 10 10 10 10
Number of Combined Input
Heaters in Thousands of Btuh Manifold & Common Vent Diameter (inches)
2 730 14 14 14 12 12 12 10 10
800 16 14 14 14 12 12 10 10
3 1095 18 18 16 16 14 14 12 12
1200 18 18 18 16 16 14 14 12
4 1460 20 20 18 18 16 16 14 12
1600 22 20 20 18 18 16 14 14
MODEL BTR(C)-500
Input: 500,000 Btuh Total Vent Height (Feet)
Draft Hood: 8” 6 8 10 15 20 30 50 100
Input Btuh Rise Vent Connector Diameter (in inches)
500,000 2 Ft. - 12 12 12 12 12 12 12
500,000 4 Ft. 12 12 12 12 12 12 10 10
500,000 6 Ft. N/A 12 12 12 12 12 10 10
Number of Combined Input
Heaters in Thousands of Btuh Manifold & Common Vent Diameter (inches)
2 1000 18 16 16 14 14 14 12 12
3 1500 22 20 20 18 16 16 14 12
4 2000 24 22 22 20 20 18 16 14
TECHNICAL DATA VENTING, TABLE 3 (Continued)

13
If a water heater is installed in a closed water system, contact the
water supplier or local plumbing inspector on how to control this
situation.
WATER (POTABLE) HEATING AND
SPACE HEATING
1. All piping components connected to this unit for space heating
applications shall be suitable for use with potable water.
2. Toxic chemicals, such as those used for boiler treatment, shall
NEVER be introduced into this system.
3. This unit may NEVER be connected to any existing heating
system or component(s) previously used with a non-potable
water heating appliance.
4. When the system requires water for space heating at
temperatures higher than required for domestic water
purposes, a tempering valve must be installed. Please refer
to installation diagrams on pages 16 through 21 in this manual
for suggested piping arrangements.
CAUTION
A closed system will exist if a check valve (without bypass),
pressurereducingvalve(withoutbypass),orawatermeter(without
bypass)isinstalledinthe cold water linebetweenthe water heater
and street main (or well).
Excessivepressuremay develop in suchclosedsystems, causing
premature tank failure or intermittent relief valve operation. This
is not a warranty failure. An expansion tank or a similar device
may be required in the inlet supply line between the appliance
and the meter or valve to compensate for the thermal expansion
of the water.
SYSTEM CONNECTIONS
The system installation must conform to these instructions and to
thelocalcodeauthority having jurisdiction. Good practice requires
that all heavy piping be supported.
THERMOMETERS (Not Supplied)
Thermometers should be obtained and field installed as shown in
the installation diagrams.
Thermometersare installedinthe system asa means of detecting
the temperature of the outlet water supply.
RELIEF VALVE
This water heater is equipped with a combination temperature-
pressure relief valve that complies with the standard for relief
valves and automatic gas shut-off devices for hot water supply
system,ANSI Z21.22-CSA4.4.FOR SAFE OPERATIONOFTHE
WATER HEATER, THE RELIEF VALVE(S) MUST NOT BE
REMOVED OR PLUGGED.
ASMEratings coverpressurerelief capacities.ANSIratings cover
release rate with temperature actuation.
In addition to the appliance relief valve, each remote storage tank
which may be used in conjunction with this appliance shall also
beinstalledwithaproperlysized, rated and approvedcombination
temperature (ANSI) and pressure (ASME) relief valve(s).
WARNING
THE PURPOSE OF RELIEF VALVE IS TO AVOID EXCESSIVE
PRESSURE OR TEMPERATURE INTO THE STEAM RANGE,
WHICH MAY CAUSE SCALDING AT FIXTURES, TANK
EXPLOSION, SYSTEM OR HEATER DAMAGE. NO VALVE IS
TO BE PLACED BETWEEN THE RELIEF VALVE AND TANK.
Your local code authority may have other specific relief valve
requirements.
A DRAIN LINE MUST BE CONNECTED TO THE RELIEF
VALVE TO DIRECT DISCHARGE TO A SAFE LOCATION TO
AVOID SCALDING OR WATER DAMAGE. THIS LINE MUST
NOT BE REDUCED FROM THE SIZE OFTHE VALVE OUTLET
AND MUST NOT CONTAIN VALVES, RESTRICTIONS NOR
SHOULD IT BE LOCATED IN FREEZING AREAS. DO NOT
THREAD OR CAP THE END OF THIS LINE. RESTRICTED
OR BLOCKED DISCHARGE WILL DEFEAT THE PURPOSE
OF THE VALVEAND IS UNSAFE. DISCHARGE LINE SHALL
BE INSTALLEDTOALLOW COMPLETE DRAINAGE OF BOTH
THE VALVE AND LINE.
See SERVICE INFORMATION section for procedure and
precautions.
GAS PIPING
Contact your local gas service company to ensure that adequate
gasservice is available andtoreview applicable installationcodes
for your area.
Size the main gas line in accordance with Table 4. The figures
shown are for straight lengths of pipe at 0.5 in. W.C. pressure drop,
which is considered normal for low pressure systems. Note:
Fittings such as elbows, tees and line regulators will add to
the pipe pressure drop. Also refer to the current edition of the
National Fuel Gas Code. For Canadian installations consult
Natural Gas and Propane Installation Code CAN/CSA-B149.1.
TABLE 4 - GAS SUPPLY LINE SIZES (IN INCHES)*
MAXIMUM CAPACITY OF PIPE IN
CUBIC FEET PER HOUR
LENGTH NOMINAL IRON PIPE SIZES (INCHES)
IN
FEET 1/2” 3/4” 1” 1 1/4” 1 1/2” 2” 2 1/2” 3” 4”
10 175 360 680 1400 2100 3960 6300 11000 23000
20 120 250 465 950 1460 2750 4360 7700 15800
30 97 200 375 770 1180 2200 3520 6250 12800
40 82 170 320 660 990 1900 3000 5300 10900
50 73 151 285 580 900 1680 2650 4750 9700
60 66 138 260 530 810 1520 2400 4300 8800
70 61 125 240 490 750 1400 2250 3900 8100
80 57 118 220 460 690 1300 2050 3700 7500
90 53 110 205 430 650 1220 1950 3450 7200
100 50 103 195 400 620 1150 1850 3250 6700
125 44 93 175 360 550 1020 1650 2950 6000
150 40 84 160 325 500 950 1500 2650 5500
175 37 77 145 300 460 850 1370 2450 5000
200 35 72 135 280 430 800 1280 2280 4600
WARNING
THEHEATERISNOT INTENDED FOR OPERATIONATHIGHER
THAN 14.0" W.C.(3.5 kPa) (1/2 POUND PER SQUARE INCH

14
GAGE- 3.5 kPa) SUPPLY GAS PRESSURE. EXPOSURE TO
HIGHER SUPPLY PRESSURE MAY CAUSE DAMAGE TO THE
GASVALVEWHICH COULD RESULTIN FIRE OR EXPLOSION.
IF OVERPRESSURE HAS OCCURRED SUCH AS THROUGH
IMPROPER TESTING OF GAS LINES OR EMERGENCY
MALFUNCTION OF THE SUPPLY SYSTEM, THE GAS VALVE
MUST BE CHECKED FOR SAFE OPERATION. MAKE SURE
THAT THE OUTSIDE VENTS ON THE SUPPLY REGULATORS
ANDTHE SAFETY VENTVALVESAREPROTECTEDAGAINST
BLOCKAGE. THESE ARE PARTS OF THE GAS SUPPLY
SYSTEM, NOT THE HEATER. VENT BLOCKAGE MAYOCCUR
DURING ICE STORMS.
IT IS IMPORTANTTO GUARDAGAINST GAS VALVE FOULING
FROM CONTAMINANTS INTHE GAS WAYS. SUCH FOULING
MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.
IF COPPER SUPPLY LINES ARE USED THEY MUST BE
INTERNALLY TINNED AND CERTIFIED FOR GAS SERVICE.
BEFOREATTACHINGTHEGASLINE,BESURE THATALLGAS
PIPE IS CLEAN ON THE INSIDE.
TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS
SUPPLY LINE,ADIRT LEG (SOMETIMES CALLED SEDIMENT
TRAPORDRIPLEG)MUSTBEINCORPORATEDINTHEPIPING
(SEE FIG. 11). THE DIRTLEG MUSTBE READILYACCESSIBLE
ANDNOT SUBJECTTOFREEZING CONDITIONS. INSTALLIN
ACCORDANCEWITHRECOMMENDATIONSOFSERVINGGAS
FIGURE 12
SUPPLIERS. REFER TO THE CURRENT EDITION OF THE
NATIONALFUELGAS CODE. ForCanadianinstallationsconsult
Natural Gas and Propane Installation Code CAN/CSA-B149.1.
To prevent damage, care must be taken not to apply too much
torque when attaching gas supply pipe to gas valve inlet.
Apply joint compounds (pipe dope) sparingly and only to the male
threads of pipe joints. Do not apply compounds to the first two
threads. Use compounds resistant to the action of liquefied
petroleum gases.
GAS PIPING AND DIRT LEG INSTALLATION
FIGURE 11

15
INSTALLATION DIAGRAMS-TOP INLET/OUTLET USAGE
GENERAL
The type, size and location of the relief valves must be in
accordance with local codes. The locations of the relief valves
shown in the installation diagrams are typical. The heater has a
factory installed high temperature limit switch and temperature
and pressure relief valve.
Cold water lines to heater should be installed as shown in order
to minimize gravity circulation of hot water to building cold water
lines.
Alisted temperature and pressurereliefvalveofadequatecapacity
is installed on the heater. The locations shown in the installation
diagrams on the following pages are typical.
The discharge opening of the temperature and pressure relief
valve, located in front of the heater must be piped to an open
drain and should not be subject to freezing temperatures.
Install in accordance with all local codes.
Use of the top inlet water connection requires installation of an
inlet dip tube (refer to figure 11). The tube is supplied in the
heater. Follow caution labels if applying heat to this fitting. Do
not allow pipe dope to contact the plastic tube during installation.
CODE RESTRICTIONS
Use of the top inlet water connection is not permitted on
installations in the state of North Carolina, due to the material of
the tube (Polypropylene). Where such code restrictions exist,
use only lower inlet tank connection. This may also require a
heat trap - check local codes. The “Top Outlet” connection may
still be used on these applications. Plug or cap all unused
openings in the tank before filling with water.
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 27. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAINADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
TUBE INLET INSTALLATION
FIGURE 13
BEFOREPLACINGTHEHEATERINOPERATION,CHECKFOR
GAS LEAKAGE. Use soap and water solution or other material
acceptable for the purpose in locating the leaks. DO NOT USE
MATCHES, CANDLES, FLAME OR OTHER SOURCES OF
IGNITION FOR THIS PURPOSE.
DISCONNECTTHE HEATERANDITSMANUALGASSHUT-OFF
VALVEFROMTHE GAS SUPPLYPIPING SYSTEM DURINGANY
SUPPLYPRESSURETESTING EXCEEDING 1/2 PSIG (3.5 kPa).
GASSUPPLYLINEMUSTBECAPPEDWHENDISCONNECTED
FROM THE HEATER FOR TEST PRESSURES OF 1/2 PSIG
(3.5 kPa) OR LESS. THE APPLIANCE NEED NOT BE
DISCONNECTED, BUT MUST BE ISOLATED FROM THE
SUPPLY PRESSURE TEST BY CLOSING THE MANUAL GAS
Shut-off VALVE.
GAS METER SIZE — NATURAL GASES ONLY
Be sure the gas meter has sufficient capacity to supply the full
rated gas input of the water heater as well as the requirements of
all other gas fired equipment supplied by the meter. If gas meter
is too small, ask the gas company to install a larger meter having
adequate capacity.
GAS PRESSURE REGULATOR
The gas pressure regulator is built into the gas valve and is
equipped to operate on the gas specified on model and rating
plate. The regulator is factory adjusted to deliver gas to burner at
correct water column pressure allowing for a nominal pressure
drop through the controls.
The minimum gas supply pressure for input adjustment must not
be less than 4.5" w.c. (1.12 kPa) for natural gas and 11.0" w.c.
(2.74 kPa) for propane gas.
Do not subject the combination gas valve to inlet gas
pressures of more than 14.0" W.C. (3.48 kPa) - natural gas,
14.0" W.C. (3.48 kPa)- propane gas. A service regulator is
necessary if higher gas pressures are encountered.
Gas pressure specified in Table 5, refer to flow pressure taken at
pressure tap of automatic gas valve while heater is operating.
GROUNDING INSTRUCTIONS
This water heater must be connected to a grounded metal,
permanent wiring system; or an equipment grounding
conductor must be run with the circuit conductors and
connected to the equipment grounding terminal or lead on the
water heater.
HEATER WIRING
Allelectrical work mustbe installed inaccordance with the current
edition of the National Electrical Code NFPA 70, for Canada use
Canadian Electric Code CSA C22.1 and must conform to all local
code authority having jurisdiction. AN ELECTRICAL GROUND
ISREQUIREDTOREDUCE RISK OFELECTRICALSHOCK OR
POSSIBLE ELECTROCUTION.
For Canadian installations the electrical connections and
grounding shall be done in accordance with current Canadian
Electrical Code CSA C22.1, Part 1 and/or local codes.
If any of the original wire as supplied with the appliance must be
replaced,use only type 105°Cthermoplasticor equivalent. 250°C
type F must be used for the flame sensor leads and the spark
ignition cable must be high voltage 250°C.

16
VERTICAL STORAGE TANK AND FORCED CIRCULATION
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROLWARNINGONPAGE 27. IF HIGHER PREHEATTEMPERATURESARE NECESSARYTOOBTAINADEQUATEBOOSTER
OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.
HORIZONTAL STORAGE TANK AND FORCED CIRCULATION

17
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 27. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE STORAGE
WITH RECIRCULATION OF SANITIZING LOOP
NOTE 1: TOGGLE SWITCH CONTROLS 180°F (82°C) WATER
CIRCULATION. INSTALL ON OR CLOSE TO DISHWASHING
MACHINE. TOGGLE SWITCH MUSTBE CLOSED (ON) DURING
THERINSEOPERATIONANDOPEN(OFF)WHENDISHWASHER
IS NOT OPERATING OR WHEN ON LONG STANDBY.
NOTE 2: INSTALL LINE TEMPERATURE CONTROL IN AN
UNINSULATED TEE BEYOND THE DISHWASHING
MACHINE TAKEOFF IN THE SANITIZING LOOP. CONTROL
SHOULD BE SETAT 185°F (85°C).
NOTE 3: ADJUST PLUG COCK SO THE SANITIZING LOOP FLOW RATE
DOESNOTCAUSEUNNECESSARYTURBULENCEINTHETANK.
* TEMPERED WATER LOOP, IF USED, CONNECT TO
POINT “A”.
**PIPE RELIEF VALVE TO OPEN DRAIN.
INSTALL IN ACCORDANCE WITH LOCAL CODES.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACKFLOW
PREVENTER, CHECK VALVE OR WATER METER WITH
CHECKVALVE.PROVISIONSFORTHERMALEXPANSIONOF
WATER IN THE HOTWATER SYSTEM MUST BE PROVIDED.

18
INSTALLATION DIAGRAMS-SIDE INLET/OUTLET USAGE
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 27. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER
SUPPLIED TO FIXTURES.
A listed temperature and pressure relief valve of adequate
capacity is installed on the heater. The locations shown in the
installation diagrams on the following pages are typical.
TWO TEMPERATURE - TWO HEATERS, ONE PRE-HEATER/ONE - BOOSTER HEATER
WITH OR WITHOUT BUILDING RECIRCULATION
The discharge opening of the temperature and pressure relief
valve must be piped to an open drain and should not be subject
to freezing conditions. DO NOT REDUCE, BLOCK OR PLUG
THE DISCHARGE OPENING OF THE VALVE.
CIRCULATING RETURN LINE CONNECTIONS
- FROMFIXTURELOOP,IFUSED, CONNECTTOPREHEATER INLET.
- FROM BOOSTED TEMPERATURE LOOP, IF USED CONNECT TO
BOOSTER INLET.
†AVALAIBLE FROM A.O. SMITH.
*PIPE RELIEF VALVE TO OPEN DRAIN.
INSTALL IN ACCORDANCE WITH LOCAL CODES.

19
ONE OR TWO TEMPERATURE - ONE HEATERS,HIGH TEMPERATURE
STORAGE WITH OR WITHOUT RECIRCULATION
HEATER WITH OR WITHOUT MIXING VALVE
HEATER WITH MIXING VALVE AND RECIRCULATED SANITIZING LOOP
NOTE 1: TOGGLE SWITCH CONTROLS 180°F (82°C)
WATERCIRCULATION. INSTALLONOR CLOSE
TODISHWASHING MACHINE. TOGGLESWITCH
MUST BE CLOSED (ON) DURING THE RINSE
OPERATION AND OPEN (OFF) WHEN
DISHWASHER IS NOT OPERATING OR WHEN
ON LONG STANDBY.
NOTE 2: INSTALL LINE TEMPERATURE CONTROL
IN AN UNINSULATED TEE BEYOND THE
DISHWASHING MACHINE TAKEOFF IN
THE SANITIZING LOOP. CONTROL
SHOULD BE SETAT 185°F (85°C).
NOTE 3: ADJUSTPLUG COCKSOTHESANITIZING
LOOP FLOW RATE DOES NOT CAUSE
UNNECESSARY TURBULENCE IN THE
TANK.
* PIPE RELIEF VALVE TO OPEN DRAIN.
INSTALL INACCORDANCE WITH LOCAL
CODES.
CIRCULATING RETURN LINE CONNECTIONS.
- TEMPERED WATER LOOP, IF USED,
CONNECT TO POINT “R”.
- STORED TEMPERATURE WATER
LOOP, IF USED, CONNECT TO COLD WATER
INLET.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACKFLOW
PREVENTER, CHECK VALVE OR WATER METER WITH CHECK VALVE.
PROVISIONS FOR THERMAL EXPANSION OF WATER IN THE HOTWATER
SYSTEM MUST BE PROVIDED.
DANGER
TEMPERATURE SETTING SHOULD NOT
EXCEED SAFE USE TEMPERATURE AT
FIXTURES. SEE WATER TEMPERATURE
CONTROLWARNINGON PAGE 27. IFHIGHER
PREHEAT TEMPERATURESARENECESSARY
TO OBTAIN ADEQUATE BOOSTER OUTPUT,
ADDANANTI-SCALD VALVE FOR HOT WATER
SUPPLIED TO FIXTURES.

20
TWO TEMPERATURE - TWO PRE-HEATERS WITH MIXING VALVE OR
BOOSTER HEATER WITH OR WITHOUT BUILDING RECIRCULATION
TWO PRE-HEATERS WITH MIXING VALVE
TWO PRE-HEATERS WITH BOOSTER HEATER
DANGER
TEMPERATURE SETTING SHOULD NOT
EXCEED SAFE USE TEMPERATURE AT
FIXTURES. SEE WATER TEMPERATURE
CONTROLWARNING ONPAGE27. IFHIGHER
PREHEATTEMPERATURESARENECESSARY
TO OBTAIN ADEQUATE BOOSTER OUTPUT,
ADDANANTI-SCALD VALVEFOR HOTWATER
SUPPLIED TO FIXTURES.