Table Of Contents; Introduction; Preparing For The Installation; Table Of Contents - A.O. Smith AOSRE50400 Instruction Manual

thank You for purchasing this water heater. Properly installed and
maintained, it should give you years of trouble free service.
Abbreviations Found In This Instruction Manual:
• ANSI - American National Standards Institute
• ASME - American Society of Mechanical Engineers
• NEC - National Electrical Code
• NFPA - National Fire Protection Association
• UL - Underwriters Laboratories Inc.

preparinG for the installation

1. Read the "General Safety" section of this manual first and then
the entire manual carefully. If you don't follow the safety rules,
the water heater will not operate properly. It could cause DEATH,
SERIOUS BODILY INJURY, AND/OR PROPERTY DAMAGE.
This manual contains instructions for the installation, operation,
and maintenance of the electric water heater. It also contains
warnings throughout the manual that you must read and
understand. All warnings and all instructions are essential to the
proper operation of the water heater and your safety. read the
entire manual Before attemptinG to install or
operate the water heater.
SAFE INSTALLATION, USE AND SERVICE................................................................................................................................................................ 
GENERAL SAFETY...................................................................................................................................................................................................... 3
INTRODUCTION .......................................................................................................................................................................................................... 4
Preparing for the Installation ................................................................................................................................................................................ 4
TABLE OF CONTENTS ................................................................................................................................................................................................ 4
TYPICAL INSTALLATION ............................................................................................................................................................................................. 5
MIXING VALVE USAGE ............................................................................................................................................................................................... 5
LOCATING THE NEW WATER HEATER ..................................................................................................................................................................... 6
Facts to Consider About Location ........................................................................................................................................................................ 6
Insulation Blankets ............................................................................................................................................................................................... 6
IMPORTANT SAFETY INSTRUCTIONS ...................................................................................................................................................................... 6
INSTALLING THE NEW WATER HEATER .................................................................................................................................................................. 7
Mounting ............................................................................................................................................................................................................... 7
Water Piping ...................................................................................................................................................................................................... 7-8
Water Piping Pressure Test .................................................................................................................................................................................. 8
Temperature-Pressure Relief Valve ................................................................................................................................................................... 8-9
Filling the Water Heater ........................................................................................................................................................................................ 9
WIRING DIAGRAM .................................................................................................................................................................................................... 0
WIRING .......................................................................................................................................................................................................................
TEMPERATURE REGULATION ................................................................................................................................................................................ 
Temperature Adjustment .................................................................................................................................................................................... 
FOR YOUR INFORMATION ....................................................................................................................................................................................... 3
Thermal Expansion ............................................................................................................................................................................................ 3
Strange Sounds .................................................................................................................................................................................................. 3
Operational Conditions ....................................................................................................................................................................................... 3
Water Odor ......................................................................................................................................................................................................... 3
"Air" in Hot Water Faucets .................................................................................................................................................................................. 3
High Water Temperature Shut Off System ......................................................................................................................................................... 3
PERIODIC MAINTENANCE ....................................................................................................................................................................................... 4
Anode Rod Inspection ........................................................................................................................................................................................ 4
Temperature-Pressure Relief Valve Operation ................................................................................................................................................... 4
Draining .............................................................................................................................................................................................................. 4
Removing Front Panel ................................................................................................................................................................................... 4-5
Thermostat Removal/Replacement .................................................................................................................................................................... 5
Element Cleaning/Replacement .................................................................................................................................................................... 15-16
High Limit Switch Removal and Replacement ................................................................................................................................................... 16
Service ............................................................................................................................................................................................................... 16
LEAKAGE CHECKPOINTS ........................................................................................................................................................................................ 7
TROUBLESHOOTING GUIDELINES ......................................................................................................................................................................... 8
REPAIR PARTS LIST ................................................................................................................................................................................................. 19

introduction

2. The installation must conform with these instructions and the
3. If after reading this manual you have any questions or do not
4. Carefully plan your intended placement of the water heater.
5. For California installation this water heater must be braced,
6. Massachusetts Code requires this water heater to be installed in

taBle of contents

4
local code authority having jurisdiction and the requirements of
the power company. In the absence of local code requirements
follow NFPA-70, the National Electrical Code (current edition),
which may be ordered from: National Fire Protection Association,
1 Batterymarch Park, Quincy, MA 02269.
understand any portion of the instructions, call the local utility or
the manufacturer whose name appears on the rating plate.
INSTALLATION OR SERVICE OF THIS WATER HEATER
REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED
TRADESMAN IN THE FIELD INVOLVED. PLUMBING
AND ELECTRICAL WORK ARE REQUIRED.
Examine the location to ensure the water heater complies with the
"Facts to Consider About the Location" section in this manual.
anchored, or strapped to avoid falling or moving during an
earthquake. See instructions for correct installation procedures.
Instructions may be obtained from California Office of the State
Architect, 400 P Street, Sacramento, CA 95814.
accordance with Massachusetts 248-CMR 2.00: State Plumbing
Code and 248-CMR 5.00.