A.O. Smith NW 37-670 - Manuals

Page 2 - DIMENSIONAL DATA

2 DIMENSIONAL DATA SIZES AND DATA 45KW THRU 720KW Model Number Inlet* & Boiler Prefix Gal.Cap. Std.KWInput D E F G** H J K S T U Outlet* Drain NW 37 45K 32 30 12 42 12 1/2 - - 20 4 42 3 1 NW 37 60K 32 30 12 42 12 1/2 - - 20 4 42 3 1 NW 37 75K 32 30 12 42 12 1/2 - - 20 4 42 2 1 NW 37 90K 32 30 12...

Page 5 - FEATURES; FOREWORD

5 APPROVALS These designs comply with requirements of Underwriters Laboratoriesand bear the U.L. label on the cabinet. All models are built to the standards of Section lV of the AmericanSociety of Mechanical Engineers. Boiler and Pressure Code,inspected and identified by this symbol. The ASME plate ...

Page 6 - INSTALLATION; General

6 IMPORTANT IT IS RECOMMENDED THAT A QUALIFIED SERVICE TECHNICIANPERFORM THE INITIAL FIRING OF THE BOILER. AT THIS TIMETHE USER SHOULD NOT HESITATE TO ASK THE TECHNICIANANY QUESTIONS WHICH THEY MAY HAVE IN REGARD TO THEOPERATION AND MAINTENANCE OF THE BOILER. BEFORE FILLING THE SYSTEM FOR OPERATION ...

Page 7 - Power Circuit

7 Calculating Amperage/Overcurrent Protection The boiler is factory wired for connection to three wire single-phaseor three and four wire three-phase branch circuits. In addition, aground conductor may be required. A diagram of the wiring is furnished with the boiler for the electrician’suse. An amp...

Page 8 - WIRING DIAGRAM 208V OR 240V THREE-PHASE (DELTA) WITH STEP CONTROL; TYPICAL WIRING DIAGRAMS

8 ELECTRICAL CONFIGURATION TABLE Boiler Type Voltage Between Control Elements Nameplate of Boiler Terminal Circuit Quantity Element Markings Service Lugs Voltage Per Operating Voltage Phase (1 Phase) Contractor Voltage 1 120 1 208 208 3 Delta (With 120 1 208 Neutral) 1 120 1 240 240 3 Delta 120 1 24...

Page 9 - SYSTEM CLEANING; OPERATION; GENERAL; WARNING; FILLING

9 WIRING DIAGRAM 480V THREE-PHASE (WYE) SYSTEM CLEANING The hot water system should be internally cleaned and flushed toremove contaminants which may have accumulated during installation.System cleaning provides chemical stability necessary for componentlife and system performance. Failure to clean ...

Page 10 - MAINTENANCE

10 4. Close the vent as water starts to flow from the opening. Place the make-up water valve in the desired position. The boiler is nowready for START UP and TEMPERATURE REGULATION if beingplaced in operation for the first time. START UP The following checks should be made by the installer when the ...

Page 11 - CHECKLIST; Not enough or no heat; SYSTEM WATER TEST; System water test

11 • Use a twisting, pulling action to remove elements scaledbeyond the size of the tank opening. • Brush loose scale from elements. • Silicates, sulfates and aluminates must be removed by scraping or other mechanical means. Lime scaledissolvents will not remove these types of scale whichare occasio...

Page 12 - NW-37 THRU NW-670 ELECTRIC HOT WATER BOILER LIMITED WARRANTY

12 NW-37 THRU NW-670 ELECTRIC HOT WATER BOILER LIMITED WARRANTY A.O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this boiler. 1. THE TANK If the tank in this boiler shall prove upon examination by the warrantor to have leaked due to natural corrosion from...