Table Of Contents; Water Temperature Control - A.O. Smith CYCLONE Xi BTH 500A Owner's Manual

ROUGH-IN DIMENSIONS ......................................................................... 
FOREWORD ............................................................................................. 
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-
Vent Pipe Termination ......................................................................... 
Direct Venting ...................................................................................... 
Direct Vent Terminal Installation ..................................................... -
Installation Sequence .......................................................................... 
Vertical Vent Terminal Installation ....................................................... 
Installation Sequence .....................................................................-3
Installation of Vent System .................................................................. 3
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 .............................................................................. 5
GAS PIPING ............................................................................................ 5
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
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

TABLE OF CONTENTS

Water (Potable) Heating & Space Heating .......................................... 7
Heater Wiring .................................................................................7-9
OPERATION ............................................................................................ 0
Sequence of Operation ....................................................................... 0
ELECTRONIC CONTROL ....................................................................... 0
Overview ............................................................................................. 0
Operating States ............................................................................0-
Adjusting the Operating Set Point ....................................................... 
Changing the Display Units ................................................................. 
Fault and Warning Conditions ........................................................-3
Access to the Current Fault or Warning .............................................. 3
Viewing the Fault History .................................................................... 24
Viewing Information About the Heater ................................................. 24
PRIOR TO START-UP REQUIRED ABILITY ........................................... 5
OPERATING INSTRUCTIONS ................................................................ 5
Adjustment Procedure (Initial Start-Up) .........................................25-26
Lighting Instructions ............................................................................ 26
Cathodic Protection ............................................................................. 7
Precautions ......................................................................................... 7
GENERAL INFORMATION ...................................................................... 7
Power Burner ...................................................................................... 7
High Limit ............................................................................................ 7
High Altitude Installations .................................................................... 7
MAINTENANCE ...................................................................................... 7
General ............................................................................................... 7
Maintenance Schedule ........................................................................ 7
Flushing ............................................................................................... 8
Draining ............................................................................................... 8
Sediment Removal .............................................................................. 8
Lime Scale Removal ......................................................................8-9
Powered Anode System ...................................................................... 9
Drain Valve and Access Panels .......................................................... 9
Relief Valve ......................................................................................... 9
Vent System ........................................................................................ 9
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
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.
3
DANGER