Table Of Contents; Features; Water Temperature Control - A.O. Smith BTH 120-250(A) Installation & Operating Instructions Manual

ROUGH-IN DIMENSIONS ...................................................................
FOREWORD ......................................................................................
FEATURES ........................................................................................
Water Temperature Control ..........................................................
High Limit Switch (E.C.O.) ............................................................
Dishwashing Machine Requirement ............................................
Circulating Pump ...........................................................................
INSTALLATION INSTRUCTIONS ........................................................ 4-13
Required Ability ............................................................................
Insulation Blankets .......................................................................
Locating The Heater .....................................................................
Clearances ...................................................................................
Hard Water ...................................................................................
Air Requirements .........................................................................
Mechanical Exhausting of Room Air ............................................
Unconfined Space .......................................................................
Confined Space ...........................................................................
Chemical Vapor Corrosion ...........................................................
Venting .........................................................................................
Vent Pipe Termination ...................................................................
Direct Venting ...............................................................................
Direct Vent Terminal Installation (Sidewall) .................................
Installation Sequence ...................................................................
Vertical Vent Terminal Installation ................................................
Installation Sequence ...................................................................
Installation of Vent System .......................................................... 10 ,11
Vent Pipe Preparation ...................................................................
CONTROL AND SWITCHES .............................................................. 11,12
Blower Prover Switch .................................................................
Blocked Outlet Prover Switch ......................................................
Blocked Inlet Prover Switch .........................................................
Low Gas Pressure Switch ..........................................................
On/Off Switch ..............................................................................
Hot Surface Igniter .......................................................................
GAS PIPING .......................................................................................
Connection of Gas Pipe ...............................................................
Purging .........................................................................................
Gas Meter Size - City Gases Only ..............................................
Gas Pressure Regulation .............................................................
Gas Valves ...................................................................................
SYSTEM CONNECTIONS ..................................................................
Thermometers ..............................................................................
Relief Valve ..................................................................................

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

PAGE
2 Water Line Connections .............................................................
2 Heater Wiring ..............................................................................
3,4 OPERATION ......................................................................................
3 Sequence of Operation ..............................................................
4 Self Diagnostic Controller ...........................................................
4 Gas Value LEDs Flashing ...........................................................
4 Error Codes .................................................................................
Fault Conditions ...........................................................................
4 No Incoming Line Voltage ............................................................
4,5 No Low Voltage ..........................................................................
5 Temperature Probe Fault .............................................................
5 E.C.O. Switch Open ....................................................................
6 Control Bad ..................................................................................
6 Combustion Air Blockage ............................................................
6 PRIOR TO START-UP .......................................................................
6 Required Ability ...........................................................................
6 OPERATIING INSTRUCTIONS ...........................................................
6 Adjustment Procedure (Initial Start-Up) ......................................
6 Lighting Instructions ....................................................................
6-8 Cathodic Protection .....................................................................
8 Precautions .................................................................................
8 GENERAL INFORMATION ................................................................
9 Power Burner .............................................................................
10 High Limit .....................................................................................
10 High Altitude Installations ............................................................
MAINTENANCE ................................................................................
11 General ........................................................................................
Maintenance Schedule ...............................................................
11 Flushing .......................................................................................
12 Draining .......................................................................................
12 Sediment Removal .......................................................................
12 Lime Scale Removal ....................................................................
12 Anode Inspection and Replacement ...........................................
12 Drain Valve and Access Panels .................................................
12 Relief Valve .................................................................................
13 Circulating Pump ..........................................................................
13 Vent System ................................................................................
13 INSTALLATION DIAGRAMS ............................................................. 23 - 27
13 Manifold Kits ................................................................................
13 CHECKLIST AND SERVICE INFORMATION ......................................
13 TROUBLE-SHOOTING ......................................................................
13 REPLACEMENT PARTS ....................................................................
13 LIMITED WARRANTY .......................................................................
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 THE TIME OF THE 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 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.
The temperature may be adjusted from 80°F/27°C to 185°F/85°C. The
thermostat was adjusted to 120°F/49°C before the heater was shipped
from the factory. It is recommended that lower water temperatures be
used to avoid the risk of scalding. It is further recommended, in all cases,
3
DANGER
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