A.O. Smith HW-300, HW-399, HW-420, HW-520, HW-670, HWB-300, HWB-399, HWB-420, HWB-520, HWB-610

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FIGURE 21

SCHEMATIC

CANADIAN MODELS, JUNCTION BOX W/6 TERMINALS

Contents

Main GAS-FIRED COMMERCIAL COPPER BOILERS FOR HYDRONIC HEATING AND HOT W A TER SUPPL Y INSTALLATION OPERATION MAINTENANCE LIMITED WARRANTY INDOOR ONLY UP-FLOW MODELS ROUGH-IN DIMENSIONS Page FOREWORD TABLE OF CONTENTS INSTALLATION INSTRUCTIONS REQUIRED ABILITY INSTALLATION AS BOILER REPLACEMENT LOCATION AIR REQUIREMENTS CHEMICAL VAPOR CORROSION INSTALLATION CLEARANCES LEVELLING SYSTEM CONNECTIONS Page Page GAS CONNECTIONS Page GAS PRESSURE REGULATORS VENTING THE BOILER - STANDARD VENTING Page MODEL HW/HWB-610 BOILER MODEL HW/HWB-300 BOILER MODEL HW/HWB-399 BOILER MODEL HW/HWB-420 BOILER TABLE 9, COMBINED VENT SIZING TABLES MODEL HW/HWB-670 BOILER VENTING MAINTENANCE - STANDARD VENTING VENTING - SIDEWALL (OPTIONAL) POWER VENT SYSTEM VENTING SYSTEM SAFETY RELIEF VALVES WIRING CONNECTIONS WARNING Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page WATER LINE CONNECTIONS HARD WATER TANK TEMPERATURE CONTROL LOW WATER CUTOFF THERMOMETERS DRAIN VALVE (Not Supplied) CLOSED WATER SYSTEM Page Page Page Page Page Page Page Page Page INSTRUCTIONS FOR NUMBERED CONTROLS SHOWN ABOVE - Page START-UP AND OPERATING INSTRUCTIONS FILLING AND VENTING PRECAUTIONS PILOT AND MAIN BURNER LIGHTING AND OPERATING INSTRUCTIONS (NATURAL AND PROPANE GAS WITH I.I.D.) WARNING: FOR YOUR SAFETY READ BEFORE OPERATING LIGHTING INSTRUCTIONS TO TURN OFF GAS TO APPLIANCE LIGHTING AND OPERATING INSTRUCTIONS PROPANE (LP) STANDING PILOT MODELS FOR YOUR SAFETY READ BEFORE LIGHTING LIGHTING INSTRUCTIONS TO TURN OFF GAS TO APPLIANCE Page Page CONTROL SETTINGS ELECTRONIC INTERMITTENT PILOT IGNITION CONTROL NORMAL OPERATING SEQUENCE WITH INTERMITTENT IGNITION CONTROLS (I.I.D.) HIGH ALTITUDE INSTALLATIONS THERMAL BALANCER COIL HIGH LIMIT CONTROL (PROTECTOR SWITCH) PRESSURE REDUCING VALVE SAFETY FLOW SWITCH SAFETY RELIEF VALVE MAINTENANCE REMOVAL OF EXISTING BOILER FROM A COMMON VENTING SYSTEM REPLACEMENT PARTS U.S. Models Canadian Models GENERAL MAINTENANCE RELIEF VALVE DANGER WARNING INTERNAL CONTAMINANTS DELIMING SOLVENTS HEAVY LIME DEPOSITS REMOVING SILICATE TROUBLESHOOTING CER-TEMP 80 RECOVERY SYSTEM CHECKOUT PROCEDURE PRE-TROUBLESHOOTING CHECKING HONEYWELL S-8600H OR S-8610M NO SPARK AT PILOT BURNER CHECKING HONEYWELL S8600H OR S-8610M SPARK AT PILOT BURNER BUT PILOT WILL NOT LIGHT Page CHECKING HONEYWELL S8600H OR S-8610M NO SPARK AT PILOT BURNER BUT PILOT WILL NOT LIGHT LIMITED WARRANTY

A.O. Smith - page 27

Models: HW-300 HW-399 HW-420 HW-520 HW-670 HWB-300 HWB-399 HWB-420 HWB-520 HWB-610