A.O. Smith 120 trough 500 User Manual

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BTR TANK TYPE HEATERS

SERVICE HANDBOOK

BTR HANDBOOK

TABLE OF CONTENTS

 

PAGE

 

PAGE

 

 

Troubleshooting (continued)

 

Introduction

1-2

Troubleshooting the Efflkal

30-31

 

 

Wire Harness Test

32

Installation

 

IID Module

33

Clearances

3-4

Pilot Spark

34

Air Requirements

5-9

Pilot Valve

35-36

Contaminated Air

10

Main Burner Test

37

Flammable

10

Flame Rectification

38

Gas Pressure

11

IID Module

39

Gas Valve

12

Main Gas Valve 40-41

 

Venting

13-15

 

 

 

 

Wiring Schematics

 

 

 

Natural and Propane Gas

42

Sequence of Operation

 

 

 

Mechanical

16

Service Charts

43

Electrical

17-18

 

 

 

 

General Questions & Answers

44

Troubleshooting

 

 

 

Transformer

19

Parts List

45-50

High Limit

20-21

 

 

Damper (on Standby)

22

Component Part Information

51

PC Board

22-23

 

 

Thermostat

24

Service Check List

52-53

Damper (call for heat)

25-26

 

 

Effikal Damper

27

Comments

54

Effikal Harness Test

28

 

 

Normal Operation

28-29

 

 

BTR WORKBOOK INTRODUCTION

This service handbook is designed to aid in servicing and troubleshooting A.O. Smith BTR water heaters in the field. No duplication or reproduction of this book may be made without the express written authorization of the A.O. Smith Water Products Company.

The following text and illustrations will provide you with a step by step procedure to verify proper installation, operation, and troubleshooting procedures. Additional quick reference data is included to assist you in servicing this product.

The information contained in this handbook is designed to answer common questions encountered in the operation of the BTR product line and is not meant to be all inclusive. If you are experiencing a problem not covered in this handbook, please contact the A.O. Smith Technical Information Department at 1-800-527-1953 or your local A.O. Smith Water Products Company representative for further assistance. This handbook is intended for use by licensed plumbing professionals and reference should be made to the installation manual accompanying the product. This handbook contains supplemental information to the BTR installation and operation manual.

A.O. Smith Water Products

1

Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

Qualifications: Installation or service of this water heater requires ability equivalent to that of a licensed tradesman in the field involved. Plumbing, air supply, venting, gas supply and electrical testing skills are required.

Tools Required:

Phillips head screwdriver

standard screwdrivers

a 3/8 and 7/16 inch open end wrench

set of marked drill bits

an electrical multimeter tester capable of measuring continuity

gas pressure gauge or manometer (gauge - AOS pt. no. 8099-2)

water pressure gauge (AOS pt. no. 4798)

thermometer (AOS pt no. 4870 - range 0 - 220 degree F)

1/2 inch socket with extension for removal of the clean out cover,

1 1/16 inch socket with extension for anode removal.

MISC: TC-043Revision 1 vs.TC-043

Revision 1:

Adds Additional model’s information.

Adds cover statement this Handbook’s also a Service Handbook for many BTC Models.

Includes Power vent kit information.

Includes BTR/C-500gas valve information.

Updated Damper illustrations.

Revision2:

Revised Part Numbers on Page 15

Revision 3:

Adds information unique to the Efflkal damper equipped (Series 110, 111 and Retrofit) models

A.O. Smith Water Products

2

Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

INSTALLATION

This portion of the handbook will review some often overlooked installation considerations, taking note of necessary installation requirements for the BTR 120 through 500 model heaters. The installation manual covers most of these items in detail.

CLEARANCES FROM COMBUSTIBLES

Clearance to Combustibles Table

MODEL

A

B

C

120 - 200

1” (2.54CM)

1” (2.54CM)

1” (2.54CM)

250 - 305

2” (5.08CM)

2” (5.08CM)

2” (5.08CM)

365 - 500

3” (7.75CM)

3” (7.75CM)

3” (7.75CM)

A 24 inch clearance for all serviceable parts is recommended. Clearances may vary between BTR models – See instruction manual or the label on the heater, for clearances applicable to your specific model.

A.O. Smith Water Products

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Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

EXTERIOR CLEARANCE

"Copyright by the American Gas Association. Used by permission of the copyright holder".

This illustrates the exterior roof clearances for BTR units with natural draft venting. The vent shall extend at least 3 feet above the highest point where it passes through a roof of a building, and at least 2 feet higher than any portion of a building within a horizontal distance of 10 feet (for vents of 12" in diameter or less). (NFPA 54 ANSI Z 223.1 SEC 7.5.2a). (Sec 7.6.2a may allow reduction to 8 feet with a “ Listed vent cap”).

A.O. Smith Water Products

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Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

AIR FOR COMBUSTION

10 CUBIC FEET OF AIR PER 1,000 BTU

 

 

10 CU.

 

 

FT.

 

+

COMB.

1,000

AIR

 

 

BTU

 

 

 

 

 

 

 

 

2.5 CU.

 

 

 

FT.

 

 

 

EXCESS

 

 

 

AIR

 

 

 

 

 

Stoichiometric or theoretical complete combustion requires 10 cubic feet of air per 1000 BTUH input of the gas input. The National Fuel Gas Code also recommends an additional 2.5 cu.ft. of "excess" air. This 12.5 cu.ft minimum supply air per 1000 BTUH input applies to natural and propane gas models.

The National Fuel Gas Code also specifies minimum make-upair opening sizes for various building installations. (Ref: NFPA 54, ANSI Z223.1, sec 5.3)

A.O. Smith Water Products

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Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

MAKE-UPAIR

DIRECT COMMUNICATION

1 Square Inch Per 4,000 BTUH

A fresh supply of make-upair for combustion can be supplied to the heater throughmake-upair ducts which directly communicate with the out of doors. Two openings are required - one within 12 inches of the top of the enclosure and one within twelve inches of the bottom of the enclosure. Each opening shall have a free area of not less than 1 square inch per 4000 BTUH of the total input of all appliances within the enclosure.

The lower opening is primarily providing combustion air. The upper opening is providing vent dilution air and acts as a relief opening for flue gases should the vent become obstructed or a downdraft condition occur. Additionally, when the heater is installed in a confined space and communicating with the outdoor air, one permanent opening, commencing within 12 in. (30 cm) of the top of the enclosure, shall be permitted where the equipment has clearances of at least 1 in. (2.5 cm) from the sides and back and 6 in. (16 cm) from the front of the appliance. The opening shall directly communicate with the outdoors and shall communicate through a vertical or horizontal duct to the outdoors or spaces (crawl or attic) that freely communicate with the outdoors, and shall have a minimum free area of:

a.1 sq. in. per 3000 BTU per hr (7 cm2 per kW) of the total input of all equipment located in the enclosure, and

b.Not less than the sum of the areas of all vent connectors in the confined space.

A.O. Smith Water Products

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Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

MAKE-UPAIR

VERTICAL DUCTS

1 Square Inch Per 4,000 BTUH

Often it is more practical to install vertical make-upair ducts to the out doors. Again, two openings are required - one within 12 inches of the top of the enclosure and one within twelve inches of the bottom of the enclosure. Each opening shall have a free area of not less than 1 square inch per 4000 BTUH of the total input of all appliances within the enclosure.

A.O. Smith Water Products

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Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS SERVICE HANDBOOK

MAKE-UPAIR

HORIZONTAL DUCTS

Daily Schedule

1 Square Inch Per 2,000 BTUH

When the heater is installed in an interior room with no roof access for vertical ducts, horizontal make-upair ducts should be installed. When using horizontal ducts, two openings are required - one within 12 inches of the top of the enclosure and one within twelve inches of the bottom of the enclosure. Each opening shall have a free area of not less than 1 square inch per 2000 BTUH of the total input of all appliances within the enclosure.

A.O. Smith Water Products

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Service Handbook

Irving, Texas ©2000

Training Department

BTR TANK TYPE HEATERS

SERVICE HANDBOOK

INSUFFICIENT MAKE-UPAIR

BACKDRAFT

Insufficient make-upair is a major cause of combustion problems. One common example is in a restaurant installation where exhaust vent equipment was not considered in sizingmake-upair requirements. This may result in air being backdrafted by the restaurant exhaust equipment through the heater causing flue gas spillage, flame roll out, improper combustion, inconsistent pilot operation, and/or erratic heater shut down.

A.O. Smith Water Products

9

Service Handbook

Irving, Texas ©2000

Training Department