A.O. Smith 300A, 500A warranty Table of Contents, Features

TABLE OF CONTENTS

ROUGH-IN DIMENSIONS	2
FOREWORD	2
FEATURES	3
Water Temperature Control	3-5
Water Temperature Setpoint Adjustment Procedure	5
High Limit Switch (E.C.O.)	5
Dishwashing Machine Requirement	5
Circulating Pump	6
INSTALLATION INSTRUCTIONS	6
Required Ability	6
Insulation Blankets	6
Locating The Heater	6
Clearances	7
Hard Water	7
Air Requirements	7
Mechanical Exhausting of Room Air	7
Unconfined Space	7
Confined Space	7
Chemical Vapor Corrosion	7
Installation Requirements for the
Commonwealth of Massachusetts	8
VENTING	8-11
Vent Pipe Termination	11
Direct Venting	11
Direct Vent Terminal Installation	11-12
Installation Sequence	12
Vertical Vent Terminal Installation	12
Installation Sequence	12-13
Installation of Vent System	13
Vent Pipe Preparation	14
CONTROLS AND SWITCHES	14
Blower Prover Switch	14
Blocked Outlet Prover Switch	14
Blocked Inlet Prover Switch	14
Low Gas Pressure Switch	14
On/Off Switch	14-15
Hot Surface Igniter	15
GAS PIPING	15
Connection of Gas Pipe	15-16
Purging	16
Gas Meter Size - City Gases Only	16
Gas Valves	16
SYSTEM CONNECTIONS	16
Thermometers	16
Relief Valve	16
Water Line Connections	16
Closed System	16-17

Water (Potable) Heating & Space Heating.	......................................... 17
Heater Wiring	17-19
OPERATION	20
Sequence of Operation	20
ELECTRONIC CONTROL	20
Overview	20
Operating States	20-21
Adjusting the Operating Set Point	21
Changing the Display Units	22
Fault and Warning Conditions	22-23
Access to the Current Fault or Warning	23
Viewing the Fault History	24
Viewing Information About the Heater	24
PRIOR TO START-UP REQUIRED ABILITY	25
OPERATING INSTRUCTIONS	25
Adjustment Procedure (Initial Start-Up)	25-26
Lighting Instructions	26
Cathodic Protection	27
Precautions	27
GENERAL INFORMATION	27
Power Burner	27
High Limit	27
High Altitude Installations	27
MAINTENANCE	27
General	27
Maintenance Schedule	27
Flushing	28
Draining	28
Sediment Removal	28
Lime Scale Removal	28-29
Powered Anode System	29
Drain Valve and Access Panels	29
Relief Valve	29
Vent System	29
INSTALLATION DIAGRAMS	30-34
Multiple Unit Installations	35
CHECKLIST AND SERVICE INFORMATION	36
Burner Operational Problems	36
Not Enough or No Hot Water	36
Water Is Too Hot	36
Water Heater Makes Sounds	36
Water Leakage is Suspected	36
TROUBLESHOOTING	36-38
REPLACEMENT PARTS	38
LIMITED WARRANTY	39

FEATURES

IMPORTANT

IT IS REQUIRED THAT A QUALIFIED SERVICE TECHNICIAN PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME THE USER SHOULD NOT HESITATE TO ASK THE TECHNICIAN ANY QUESTIONS WHICH HE MAY HAVE IN REGARD TO THE OPERATION AND MAINTENANCE OF THE UNIT.

A CHECKLIST AND SERVICE INFORMATION section are included at the rear of this manual. By using this checklist the user may be able to make minor operational adjustments and save himself unnecessary service calls. However, the user should not attempt repairs which are not listed in this section.

WATER TEMPERATURE CONTROL

DANGER

THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE THERMOSTAT TO CONTROL WATER TEMPERATURE. HOT WATER TEMPERATURES REQUIRED FOR AUTOMATIC DISHWASHER AND LAUNDRY USE CAN CAUSE SCALD BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/OR DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS VARIES WITH THE PERSON’S AGE AND TIME OF EXPOSURE. THE SLOWER RESPONSE TIME OF CHILDREN, AGED OR DISABLED PERSONS INCREASES THE HAZARDS TO THEM. NEVER ALLOW SMALL CHILDREN TO USE A HOT WATER TAP, OR TO DRAW THEIR OWN BATH WATER. NEVER LEAVE A CHILD OR DISABLED PERSON UNATTENDED IN A BATHTUB OR SHOWER.

THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO

SET TEMPERATURES.

The water temperature is controlled using the Temperature Control Up/Dn Button on the Display at the front of the unit (See Figure 1). This control utilizes two temperature probes to determine the tank temperature. The primary temperature probe is located at the top of the tank and the other is near the water inlet.