A.O. Smith HW-420 User Manuals

Table of Contents

• ROUGH-IN DIMENSIONS

  2
• START-UP AND OPERATING INSTRUCTIONS

  45
• FOREWORD

  4
• Filling And Venting

  46
• INSTALLATION INSTRUCTIONS

  4
• Pilot and Main Burner

  46
• Lighting Instructions

  47
• Required Ability

  4
• Pilot and Main Burner (Continued)

  49
• Installation As Boiler Replacement

  4
• Electronic Intermittent Pilot Ignition Control

  51
• Location

  5
• Air Requirements

  5
• S-8610M Intermittent Ignition Control (I.I.D.)

  52
• Chemical Vapor Corrosion

  6
• High Altitude Installations

  52
• Installation Clearances

  6
• Thermal Balancer

  52
• Levelling

  6
• Coil High Limit Control (Protector Switch)

  52
• System Connections

  6
• Pressure Reducing Valve

  53
• Gas Connections

  9
• Safety Flow Switch

  53
• Gas Pressure Regulators

  11
• Safety Relief Valve Maintenance

  54
• Venting The Boiler - Standard Venting

  12
• Replacement Parts

  54
• Venting Maintenance - Standard Venting

  15
• Venting Sidewall (Optional) Power Vent System

  15
• VENTING SYSTEM

  54
• Venting System

  15
• GENERAL MAINTENANCE

  55
• Relief Valve

  55
• Safety Relief Valves

  15
• CLEANING AND FLUSHING INSTRUCTIONS

  55
• Wiring Connections

  16
• Internal Contaminants

  55
• Water Line Connections

  32
• Hot Water Supply Boilers - Preventive Maintenance

  55
• Hard Water

  32
• Deliming

  55
• Tank Temperature Control

  32
• Deliming Solvents

  56
• Low Water Cutoff

  33
• Heavy Lime Deposits

  56
• Thermometers

  33
• Removing Silicate

  56
• Drain Valve (Not Supplied)

  33
• PRE-TROUBLE-SHOOTING

  57
• Closed Water System

  33
• TROUBLE-SHOOTING

  57
• Piping Diagrams

  34
• LIMITED WARRANTY

  62