A.O. Smith TC-049-R2 Service Handbook
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A.O. Smith TC-049-R2 Service Handbook

A.O. Smith TC-049-R2 Service Handbook

A.o. smith residential gas & electric water heater service handbook
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A.O. SMITH
SERVICE HANDBOOK
Residential Gas and Electric

Water Heaters

Prepared by the Technical Training
Asland City, Tennessee
Department
he first portion of this Service Handbook addresses service issues
T
associated with Residential Gas Water Heaters that are atmospherically
vented and use a thermocouple as their electrical source.
The second portion of this Handbook addresses service issues of
Residential Electric Water Heaters having one or two heating elements
and common wiring configurations for these models.
Printed in USA 0402
$15.00
Part No. TC-049-R2

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Summary of Contents for A.O. Smith TC-049-R2

  • Page 1: Water Heaters

    The second portion of this Handbook addresses service issues of Residential Electric Water Heaters having one or two heating elements and common wiring configurations for these models. Printed in USA 0402 $15.00 Part No. TC-049-R2...

  • Page 2: Table Of Contents

    This service handbook is designed to aid in servicing and troubleshooting A.O. Smith Residential Gas and Electric 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.

  • Page 3: Tools

    – to drain tank container – to measure gallons per minute flow Rev 1 adds Technical Bulletins Rev 2 corrects illustration errors A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Qualifications Training Department Ashland City, Tennessee...

  • Page 4: General Section

    Pounds X .45359 = Kilogram Gallons X 3.7854 = Liters = (Mixed Temp. – Cold) divided by (Hot Temp. – Cold) % of Hot A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK SERVICE GUIDELINES is the heat required to raise 1 pound of water 1 F...

  • Page 5: Construction

    All water heaters will contain at least (to prevent water temperatures approaching the “steam” level). limit A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK bonded to the steel. This prevents water...
  • Page 6 Air Is Drawn In For Combustion. Keep Area Clean And Free From Flammables And Flammable Vapors Installation Must Follow Local Codes and Instruction Manual Guidelines A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Exhaust Vent to Outside of Building Union...

  • Page 7: Control

    There is one control on this style of water heater. The control has a Contro main gas regulator, pilot gas regulator, on-off-pilot knob, controls water temperature, has a temperature adjustment knob, and a high water temperature limit safety. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK (delta) Note: The word “Hot”...

  • Page 8: Burner

    DANGER! If the pilot is extinguished, it can take up to 180 seconds for the thermocouple to cool sufficiently to close the safety valve. A.O. Smith Water Products Company Training Department Ashland City, Tennessee...

  • Page 9: Temperature

    When the top knob is turned to the “ON” position, gas is also available to the main burner if the thermostat calls for heat. A.O. Smith Water Products Company Training Department Ashland City, Tennessee ©2002...

  • Page 10: Water Flow

    30° F. Setting Approximate Temperature (°F) Time To Cause Injury Hot (▲) Very Hot A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK 120° ± 10° 130° ± 10°...

  • Page 11: Service

    Lack of Oxygen: dilution, the result will be: Pilot outage Yellow burner flame Sooting water heater Possible carbon monoxide Smell of burnt gas in the room A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK 1,000 Fuel (Enters Here) 12.5 Cubic...
  • Page 12 +/- .3 inch W.C. from desired Additional considerations when pilot or main burner flames are too large or too small: Incorrect orifice Dirt in orifice or gas supply tubing A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Testing with Pressure...

  • Page 13: Procedures And Conditions

    Light the pilot and continue to hold this knob down while conducting the test. If … reading test of at least 13 MV is not present reading test of at least 13 MV is present A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then check for lack of supply air.
  • Page 14 Increased combustion efficiency – higher thermal efficiency means that an increased amount of heat is transferring from the flue gas into the water. If you transfer (approximately) 87.5%, or more, the moisture in the flue gas will condense. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK …...
  • Page 15 If … any of the above conditions exist Suggested Multiple Heater Water Piping Required For Proper Operation of Top Connect Models A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then raise the supply air temperature or...

  • Page 16: Exhaust Venting Notes

    (the A.G.A. symbol). A sample might be: Model “PGCG-50 – 242” “Ser No. MB99-(numbers) – 242”. To order parts, contact your local A.O. Smith Contractor or Distributor, phone AOS parts at 800-433-2545 or contact A. O. Smith on Web site “www.hotwater.com”...

  • Page 17: Installation

    RATING PLATE WITH MODEL AND SERIAL NUMBER SEE MANUAL AND LABELS INSTALLATION CLEARANCES INSTALLATION MUST FOLLOW LOCAL CODES AND INSTRUCTION MANUAL GUIDELINES. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK INSTALLATION TO †FUSED ELECTRICAL SUPPLY (BREAKER BOX) UNION COLD WATER...
  • Page 18 Tank Type, Water Heaters. The illustrations are for two element models but the information also applies to single element models. Multiple Heater Water Piping Required for Proper Operation of Top Connect Models TEMPERATURE/PRESSURE RELIEF VALVES A.O. Smith Water Products Company Training Department Ashland City, Tennessee ©2002...

  • Page 19: Guidelines

    (If they operate at the same time, amperage draw doubles, wire gauge size increases, fuse size increases and little is gained in heat recovery.) A.O. Smith Water Products Company Training Department Ashland City, Tennessee...
  • Page 20 Voltage Notes: 120 volt AC circuit (Hot) L1 to Ground = 120 Volts L2 to Ground = 0 Volts A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK (Hot) L1 or L2 to Ground = 120 Volts L1 L2 = 240 Volts...
  • Page 21 Older 59T controls had a maximum setting of 170°F. Replacement 59T controls will stop at 150°F. 89T controls are combination High Limit/Thermostat, one piece controls. 66T limits may be mounted onto 59T thermostats. 66T4400 59T4100 A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Newer Older Models Models...

  • Page 22: C-2 Circuit

    After having confirmed that the water heater has been installed per the installation manual instructions: C-2 Circuit Single element Single thermostat Single High Limit A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK C-2 Circuit Prior to 1996 Power Enters High Limit 1 and 3...

  • Page 23: Thermostat

    Through High Limit L1 to T2 and L3 to L4 Thermostat T2 Contacts Open A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Note: If used on a normally two element heater, controls will be located behind the upper service cover and the element behind the lower service cover.

  • Page 24: A-6 Circuit

    Power Enters High-Limit Through High Limit 1, 4 Contacts Open Power Interrupted to Upper Element Upper Thermostat, 1, 2 Open A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK A-6 CIRCUIT Upper Thermostat 1, 2 Contacts Closed Power to Upper Element...

  • Page 25: Wiring Diagram

    Operation: From cold tank of water Power Enters High-Limit Through High Limit Upper Thermostat Contacts Open Power Interrupted to Upper Element Open A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK A-6 Circuit - Post 1995 Contacts Closed Power to Upper /Element Element Heats Water...
  • Page 26 “Off Peak” meter, which interrupts power to the lower element during the time of day when electricity is more expensive. This customer relies on additional hot water storage to meet their needs while this element is off. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK...
  • Page 27 To Lower High Limit 1. Lower High Limit 1, 2 Is Closed Lower Thermostat 1, 2 Is Closed Lower Element Heats Bottom 2/3 Of Tank A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK A-7 Circuit Prior to 1996 Fused Disconnect...

  • Page 28: Wiring Diagram

    2 Thermostats 2 High Limits 4 Wire Four wire circuit for non-simultaneous element operation. This circuit permits off-peak meter usage and connection to 3 phase supply circuit. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK WIRING DIAGRAM A-7 – Post 1995 *Interrupts power to lower element during “peak”...
  • Page 29 Upper Thermostat 3, 4 Closes Power Flows Between Upper Thermostat 4 and Lower High Limit L1 Lower High Limit L1 and Lower Thermostat T2 is Closed A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK A-7 Circuit Post 1995 Fused Disconnect...

  • Page 30: Certification And Approvals

    The following paragraph describes the relationship between ASHRAE, NAECA and the Department of Energy’s ENERGY FACTOR as it relates to the residential electric product lime. All of the A.O. Smith residential electric water heaters meet this code. The American Society of Heating, Refrigeration and Air Conditioning Engineer (ASHRAE) guidelines follow the National Appliance Energy Conservationist Act (NAECA).

  • Page 31: Simultaneous Dual Elements

    Note: Residential heaters may or may not offer the ability to wire elements for simultaneous operation. If they are wired for non-simultaneous operation, amperage will be as if wired single phase. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK 3 Supply Wires...

  • Page 32: Service

    (+7.5%) is present meter reads "0" meter reads "1" or off scale ** The above test can also be conducted with the element removed from the tank. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK SERVICE … then continue testing.
  • Page 33 Test voltage between 4 and 2 or T2 and L4 If … rated voltage is not present rated voltage is present A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Voltage Checks … then check circuit breaker (fused disconnect)

  • Page 34: C-2 Service

    Test between 4 and 2 or L4 and T2 If … rated voltage is present lower than rated voltage is present no voltage is present A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then check wiring from control. repeat Ohms resistance test of element check for water leaks in piping or fixtures.
  • Page 35 59T4000 Test around red wire then black wire to element. If … amperage is noted (indicating flowing power) amperage is not noted A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK must push the high limit reset … then replace the element.
  • Page 36 (+7.5%) is present meter reads "0" meter reads "1" or off scale ** The above test can also be conducted with the element removed from the tank. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK A-6 Circuit Servicing … then continue testing.

  • Page 37: A-6 Service

    NOT present Test between 2 and 4 or L1 and L4 If … correct supply voltage is present correct supply voltage is NOT present, still no power A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Voltage Check … then continue.
  • Page 38 Test between high limit 4 and lower thermostat 2 or L4 and 2 If … correct supply voltage is present correct supply voltage is not present A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then continue.

  • Page 39: Grounded Element Test

    (+5, - 10%) meter reads approximately ½ of the proper amperage meter reads NO amperage A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Amperage Method - using “clamp type” Amperage – must push the high limit reset …...
  • Page 40 If the consumer uses enough of the stored hot water to drop tank temperature at the top of the tank to call for upper element activation, then the upper element will reheat the upper third of the tank A.O. Smith Water Products Company Training Department Ashland City, Tennessee...

  • Page 41: A-7 Service

    (+7.5%) is present meter reads “0” meter reads “1” or off scale ** The above test can also be conducted with the element removed from the tank. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then continue testing.

  • Page 42: Voltage Checks

    Test between upper high limit 4 and upper thermostat 2 If … the proper voltage is not present high limit and upper thermostats 2 the proper voltage is present A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Voltage Checks … then check power from the breaker (fused disconnect).
  • Page 43 Test between lower high limit 2 and 4 or L1 and L4 If … proper voltage is not present pushing reset restored voltage pushing reset did not restore voltage proper voltage is present A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then replace upper thermostat. continue to next step.
  • Page 44 Test between the terminals of the lower element If … proper voltage is not present: proper voltage is present: A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then check jumper between lower high limit 2 and lower thermostat 1.
  • Page 45 ½ of the proper amperage meter reads NO amperage Note: Amperage will only be indicated while electricity flows through a wire. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK … then the thermostat is calling for heat...
  • Page 46 57.7 92.8 74.3 Rated Voltage 3000 3500 4.64 14.4 12.4 18.6 15.9 25.6 21.9 76.8 65.7 A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK Element with Links Rated Wattage 1000 1250 1500 13.9 11.1 9.28 43.3 34.6 28.8 55.7 44.6 37.1...

  • Page 47: A.o. Smith Technical Bulletins

    Chlorination Procedure... 54 Not Enough Hot Water - Gas ... 55 Not Enough Hot Water – Electric ... 56 Thermal Expansion ... 57 Leaking Temperature and Pressure Relief Valve... 59 A.O. Smith Water Products Company Training Department Ashland City, Tennessee ©2002...
  • Page 48 Mineral buildup in some heaters prevents them leaking while greatly reducing efficiency. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK A Temperature and Pressure Relief Valve limits pressure to a maximum.
  • Page 49 For more detailed explanation on this information as well as additional service information, see the A.O. Smith Web site www.hotwater.com 0801 form TC-063 A.O. Smith Water Products Company ©2002...

  • Page 50: Water Hammer

    Arrestors should be located as close as possible to the source of the shock wave. Since water hammer exposes the equipment to pressures in excess of its design NOTES limits, failures caused by water hammer are not eligible for warranty consideration. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK TECHNICAL BULLETIN...

  • Page 51: Mineral Buildup

    The directions on the product should be followed explicitly. For additional information and instructions in deliming water heaters and NOTES boilers, please refer to the following pamphlets available from A.O. Smith: Why? When & How: To Remove Water Scale from Tank Type Water Heaters...

  • Page 52: Aluminum Hydroxide

    On electric models, return the wiring to its original configuration. Turn heater fuel “ON”. Since aluminum hydroxide is a product of a chemical reaction dependent on the water condition, NOTE any treatment is not considered warranty related. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK TECHNICAL BULLETIN BULLETIN 14 ALUMINUM HYDROXIDE GAS - Heat for 7 to 10 minutes.

  • Page 53: Discolored Water

    See Bulletin 23 for the chlorination procedure. Since rusty water is caused by a bacteria presence and is not caused by the NOTE water heater, any treatment would not be considered warranty related. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK TECHNICAL BULLETIN...

  • Page 54: Smelly Water

    Since smelly water is caused by a bacteria presence and is not caused by the NOTE water heater, any treatment would not be considered warranty related. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK TECHNICAL BULLETIN...

  • Page 55: Chlorination Procedure

    Return hot water heating system to service by following the recommended STEP 13 start-up procedure posted on the unit or in the manual. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK TECHNICAL BULLETIN BULLETIN 23...

  • Page 56: Not Enough Hot Water - Gas

    STEP 9 Step 6 - if the temperature was not within range, check the thermostat. THE FIX Step 9 - if more than 30 F was lost, check the dip tube. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK TECHNICAL BULLETIN...

  • Page 57: Not Enough Hot Water - Electric

    Step 6 - if the temperature was not within range, check the thermostats. THE FIX Step 9 - if more than 30 F was lost, check the lower element for continuity and the dip tube. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK TECHNICAL BULLETIN...

  • Page 58: Thermal Expansion

    The temperature and pressure relief valve (T&P) or PRV should open and release water once the pressure reaches the maximum setting on the valve. The valve will close once the pressure falls below the pressure setting of the valve. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK...
  • Page 59 These failures are not covered by the manufacturer’s warranty, so it is extremely important that everyone be aware of the causes, symptoms and solutions to thermal expansion in a closed water heating system. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK...

  • Page 60: Leaking Temperature And Pressure Relief Valve

    Large volume of hot water sporadically discharged from the relief valve - The relief valve relieves water quickly when actuating on temperature. The only cause of this problem is a malfunctioning thermostat. A.O. Smith Water Products Company ©2002 SERVICE HANDBOOK...
  • Page 61 For every technical problem, there is a solution! A.O. Smith Water Products Company proudly introduces our service handbooks and product training CDs. To place an order, call 1-800-433-2545 or go to www.hotwater.com/parts Click the “Parts” tab • • Go to “Product Code” and select “Service and Training Materials”...

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