A.O. Smith Dve-52, Dve-80, Dve-120 User Manual

0 (0)

Instruction Manual

COMMERCIAL ELECTRIC WATER HEATERS

500 Tennessee Waltz Parkway

Ashland City, TN 37015

ASME

(OPTIONAL)

Thank you for buying this energy efficient water heater. We appreciate your confidence in our products.

MODELS DRE-52/80/120 SERIES 100 & DVE-52/80/120 SERIES 100

INSTALLATION - OPERATION - SERVICE - MAINTENANCE - LIMITED WARRANTY

place these instructions adjacent to heater and notify owner to keep for future reference.

PRINTED IN THE U.S.A 0908

1

196674-002

 

 

SAFE INSTALLATION, USE, AND SERVICE

The proper installation, use and servicing of this water heater is extremely important to your safety and the safety of others.

Many safety-related messages and instructions have been provided in this manual and on your own water heater to warn you and others of a potential injury hazard. Read and obey all safety messages and instructions throughout this manual. It is very important that the meaning of each safety message is understood by you and others who install, use, or service this water heater.

This is the safety alert symbol. It is used to alert you to potential personal injury hazards. Obey all safety messages that follow this symbol to avoid possible injury or death.

 

 

 

 

DANGER indicates an imminently hazardous

 

 

DANGER

 

 

 

 

 

 

 

situation which, if not avoided, could result

 

 

 

 

in death or injury.

 

 

 

 

 

 

 

 

 

 

 

 

 

WARNING indicates a potentially hazardous

 

 

WARNING

 

 

 

 

 

 

 

situation which, if not avoided, could result

 

 

 

 

in death or injury.

 

 

 

 

 

 

 

 

 

 

 

 

 

CAUTION indicates a potentially hazardous

 

 

 

 

 

 

 

 

 

 

CAUTION

 

situation which, if not avoided, may result

 

 

 

in minor or moderate injury.

 

 

 

 

 

 

 

 

 

 

 

 

CAUTION used without the safety alert

 

 

 

 

 

CAUTION

 

symbol indicates a potentially hazardous

 

 

situation which, if not avoided, could result

 

 

 

 

in property damage.

 

 

 

 

 

 

 

 

 

All safety messages will generally tell you about the type of hazard, what can happen if you do not follow the safety message, and how to avoid the risk of injury.

The California Safe Drinking Water and Toxic Enforcement Act requires the Governor of California to publish a list of substances known to the State of California to cause cancer, birth defects, or other reproductive harm, and requires businesses to warn of potential exposure to such substances.

This product contains a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm. This appliance can cause low level exposure to some of the substances listed, including formaldehyde.

IMPORTANT DEFINITIONS

Qualified Installer or Service Agency:

Installation and service of this water heater requires ability equivalent to that of a Qualified Agency (as defined by ANSI below) in the field involved. Installation skills such as plumbing, electrical supply are required in addition to electrical testing skills when performing service.

ANSI Z223.1 2006 Sec. 3.3.83:

“Qualified Agency” - “Any individual, firm, corporation or company that either in person or through a representative is engaged in and is responsible for (a) the installation, testing or replacement of gas piping or (b) the connection, installation, testing, repair or servicing of appliances and equipment; that is experienced in such work; that is familiar with all precautions required; and that has complied with all the requirements of the authority having jurisdiction.”

2

GENERAL SAFETY INFORMATION

PRECAUTIONS

DO NOT USE THISAPPLIANCE IFANY PART HAS BEEN UNDER WATER. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system which has been under water.

If the unit is exposed to the following, do not operate heater until all corrective steps have been made by a qualified service agency.

1.External fire.

2.Damage.

3.Firing without water.

GROUNDING INSTRUCTIONS

This water heater must be grounded in accordance with the National Electrical Code and/or local codes. These must be followed in all cases. Failure to ground this water heater properly may also cause erratic control system operation on ELECTRONIC

CONTROL models.

This water heater must be connected to a grounded metal, permanent wiring system; or an equipment grounding conductor must be run with the circuit conductors and connected to the equipment grounding terminal or lead on the water heater.

HYDROGEN GAS (FLAMMABLE)

Hydrogen gas can be produced in a hot water system served by this heater that has not been used for a long period of time (generally two weeks or more). Hydrogen gas is extremely flammable. To reduce the risk of injury under these conditions, it is recommended that the hot water faucet be opened for several minutes at the kitchen sink before using any electricalapplianceconnectedtothehotwatersystem.Ifhydrogenispresent therewillprobablybeanunusualsoundsuchasairescapingthroughthepipe as the water begins to flow. THERE SHOULD BE NO SMOKING OR OPEN FLAME NEAR THE FAUCET AT THE TIME IT IS OPEN.

When servicing this unit, verify the power to the unit is turned off prior to opening the control cabinet door.

3

TABLE OF CONTENTS

SAFE INSTALLATION, USE AND SERVICE.....................................

2

Thermostat Settings – Electronic Control Models....................

21

GENERAL SAFETY INFORMATION.................................................

3

ELECTRONIC CONTROL MODELS OPERATION.........................

21

TABLE OF CONTENTS.....................................................................

4

Control System Features..........................................................

21

INTRODUCTION................................................................................

4

Control System Navigation.......................................................

21

Preparing for the New Installation..............................................

4

Desktop Screen...................................................................

21-23

DIMENSIONS AND CAPACITIES DATA............................................

5

Temperatures Menu

23-24

APPROVALS

6

Temperature Settings

24

FEATURES AND COMPONENTS

7-8

Heater Status Menu

25

LOCATING THE NEW WATER HEATER

9

Economy Mode Setup Menu

25-26

INSTALLATION

10

Economy Mode Settings

26-28

Required Ability

10

Alarm Output Setup Menu

29

General.....................................................................................

10

Mixing Valve Usage..................................................................

10

Display Settings Menu.............................................................

29

Chemical Vapor Corrosion.......................................................

10

Heater Information Menu....................................................

29-30

Circulating Pump......................................................................

10

Current Fault / Alert Menu........................................................

30

Insulation Blankets...................................................................

10

Fault Occurrence Menu............................................................

30

Temperature-Pressure Relief Valve.....................................

10-11

Restore Factory Defaults Menu..........................................

30-31

Water Line Connection.............................................................

11

MAINTENANCE...............................................................................

31

Closed Water System...............................................................

11

General................................................................................

31-32

Thermal Expansion..................................................................

11

Flushing....................................................................................

32

ELECTRICAL...................................................................................

12

Sediment Removal

32

OPERATION

19

Water and Lime Scale Removal

32

General

19

TROUBLESHOOTING CHECKLIST

33

Filling the Water Heater

19

Not Enough or No Water

33

Start Up

19

Water Heater Makes Strange Sounds

33

Draining the Water Heater

19

If You Cannot Identify or Correct the Source of Malfunction

17

TEMPERATURE REGULATION......................................................

20

High Temperature Devices.......................................................

20

Leakage Checkpoints...............................................................

34

Thermostat Controls.................................................................

20

PIPING DIAGRAMS....................................................................

35-42

Thermostat Settings – Surface Mount Control Models............

20

WARRANTY.....................................................................................

43

INTRODUCTION

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

• GAMAGasAppliance Manufacturer’sAssociation

• NEC - National Electrical Code

• NFPANational Fire ProtectionAssociation

• UL - Underwriters Laboratory

Preparing for the Installation

1.Read the “General Safety Information” section of this manual first and then the entire manual carefully. If you don’t follow the safety rules, the waterheatermaynotoperatesafely.ItcouldcauseDEATH,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 be aware of. 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.

Detailed installation diagrams are in this manual. These diagrams will serve to provide the installer with a reference for the materials and method of piping suggested. IT IS NECESSARY THAT ALL WATER PIPING AND THE ELECTRICAL WIRING BE INSTALLED AND CONNECTEDAS SHOWN IN THE DIAGRAMS.

Particular attention should be given to the installation of thermometers at the locations indicated in the diagrams as these are necessary for checking the operation of the heater.

Be sure to turn off power when working on or near the electrical system of the heater. Never touch electrical components with wet hands or when standing in water. When replacing fuses always use the correct size for the circuit. see page 13.

The principal components of the heater are identified on pages 7 & 8. The model and rating plate on page 6 interprets certain markings into useful information. Both of these references should be used to identify the heater, its components and optional equipment.

2.The installation must conform with these instructions and the local code authority having jurisdiction and the requirements of the power company. In the absence of code requirements, follow NFPA-70 (current edition). In the absence of local codes, the installation must comply with the latest editions of the National Electrical Code, NFPA 70 or the Canadian Electrical Code CSA C22.1. The National Electrical Code may be ordered from: National Fire Protection Association, 1 Batterymarch Park, Quincy, MA02269.The Canadian ElectricalCodeisavailablefromtheCanadianStandardsAssociation, 8501 East Pleasant Valley Road, Cleveland, OH 44131.

3.If after reading this manual you have any questions or do not understand any portion of the instructions, call the toll free number listed on the back cover of this manual for technical assistance.

A sample rating plate is shown on page 6 of this manual. In order to expedite your request, please have full model and serial number available for the technician.

4.Carefully plan your intended placement of the water heater. Examine the location to ensure the water heater complies with the “Locating the New Water Heater” section in this manual.

Installation and service of this water heater requires ability equivalent to that of a licensed tradesman or qualified agency (page 2) in the field involved. Plumbing and electrical work are required.

5.For installation in California this water heater must be braced or anchored to avoid falling or moving during an earthquake. See instructions for correct installation procedures. Instructions may be obtained from California Office of the StateArchitect, 1102 Q Street, Suite 5100, Sacramento, CA 95811.

6.Massachusetts Code requires this water heater to be installed in accordancewithMassachusetts248-CMR2.00:StatePlumbingCode and 248-CMR 5.00.

4

dimensions and capacities data

DRE/DVE MODEL DIFFERENCES

This Instruction Manual covers two models of commercial electric water heaters; DRE models and DVE models. These two models are equipped from the factory with different controls.

DRE models are factory equipped with surface mounted thermostat/ECO combination controls. DVE models are factory equipped with an electronic control system.

In this Instruction Manual “DRE” models are referred to as: “Surface Mount Control” models.

In this Instruction Manual “DVE” models are referred to as: “Electronic Control” models.

Model Number

Tank Capacity in Gallons (Liters)

A - Inches (mm)

B - Inches (mm)

C - Inches (mm)

Inlet/Outlet

 

 

 

 

 

 

DRE/DVE-52

50 (189.3)

55 3/4 (1416)

21 3/4 (552)

27 (685)

1 1/4

DRE/DVE-80

80 (302.8)

60 1/4 (1350)

25 1/2 (648)

31 (787)

1 1/4

DRE/DVE-120

119 (450.5)

62 1/4 (1581)

29 1/2 (749)

35 (889)

1 1/4

RECOVERY RATE IN GALLONS PER HOUR*

Temperature Rise °F

Standard

BTU/

 

 

 

 

 

 

 

 

 

 

 

 

KW Input

Hour

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

20,478

82

62

49

41

35

31

27

25

22

21

19

18

9

30,717

123

92

74

62

53

46

41

37

34

31

28

26

12

40,956

164

123

98

82

70

61

55

49

45

41

38

35

13.5

46,075

184

138

111

92

79

69

62

55

50

46

43

40

15

51,195

205

154

123

102

88

77

68

61

56

51

47

44

18

61,434

246

184

148

123

105

92

82

74

67

61

57

53

24

81,912

328

246

197

164

140

123

109

98

89

82

76

70

27

92,151

369

276

221

184

158

138

123

111

101

92

85

79

30

102,390

410

307

246

205

176

154

137

123

112

102

95

88

36

122,868

492

369

295

246

211

184

164

148

134

123

113

105

40.5

138,226

554

418

3332

277

237

208

1185

166

151

138

128

119

45

153,585

615

461

369

307

263

230

205

184

168

154

142

132

54

184,302

738

553

443

369

316

277

246

221

201

184

170

158

*Figured at 1 KW (3413 Btu) = 4.1 gallons at 100°F temperature rise.

To determine recovery rate per minute, divide recovery rate per hour by 60.

5

APPROVALS

All models meet

All models are listed

National Sanitation

by Underwriters

Foundation NSF-5

Laboratories Inc.

requirements.

 

MODEL AND RATING

6

FEATURES AND COMPONENTS

ELECTRONIC CONTROL MODELS

FIGURE 1

7

FEATURES AND COMPONENTS

SURFACE MOUNT CONTROL MODELS

FIGURE 2

8

LOCATING THE NEW WATER HEATER

Facts to Consider About the Location

Carefully choose a location for the new water heater. The placement is a very important consideration for the safety of the occupants in the building and for the most economical use of the appliance.

Whether replacing an old water heater or putting the water heater in a new location, the following critical points must be observed. The water heater must be located:

1.On a level surface. Shim the channel type skid base as necessary if levelling is required.

2.Near a floor drain. The heater should be located in an area where leakage of the tank or connections will not result in damage to the area adjacent to the heater or to lower floors of the structure.

3.Close to the point of major hot water usage and the power supply.

Hot water piping and branch circuit wiring should be as short as possible.

Insulate hot and cold water piping where heat loss and condensation may be a problem.

Heater construction permits installation, maintenance, and service work to be performed through the front control panel.

Suggested clearances from adjacent surfaces are 12 inches on top, 30 inches in front for access to the unit.

The heater may be installed on or against combustible surfaces. The left side and back may be placed flush against adjacent surfaces.

The temperature of the space in which the water heater is installed must not go below 32°F or above 122°F.

9

INSTALLATION

REQUIRED ABILITY

Installation and service of this water heater requires ability equivalent to that of a qualified agency (page 2) in the field involved. Plumbing

and electrical work is required.

general

The installation must conform with these instructions and the local code authority having jurisdiction and the requirements of the power company. In the absence of code requirements, follow NFPA70 (current edition). In the absence of local codes, the installation must comply with the latest editions of the National Electrical Code, NFPA 70 or the Canadian Electrical Code CSA C22.1. The National Electrical Code may be ordered from: National Fire Protection Association, 1 Batterymarch Park, Quincy, MA02269. The Canadian ElectricalCodeisavailablefromtheCanadianStandardsAssociation,

8501 East Pleasant Valley Road, Cleveland, OH 44131.

Do NOT test electrical system before heater is filled with water, follow the START UP procedure in the OPERATION section of this manual.

The principal components of the heater are identified in the Features and Components illustrations on pages 6 and 7.

MIXING VALVE USAGE:

Water heaters are intended to produce hot water. Water heated to a temperature which will satisfy space heating, clothes washing, dish washing, cleaning and other sanitizing needs can scald and permanently injure you upon contact. Some people are more likely to be permanently injured by hot water than others. These include the elderly, children, the infirm, or physically/developmentally disabled. If anyone using hot water in your home fits into one of these groups or if there is a local code or state law requiring a maximum water temperature at the hot water tap, then you must take special precautions. In addition to using the lowest possible temperature setting that satisfies your hot water needs, a means such as a MIXING VALVE, should be used at the hot water taps used by these people or at the water heater.

MIXING VALVES for reducing point of use temperature are available. Consult a qualified installer or service agency. Follow all manufacturer’s Instructions for installation of these valves. Before changing the factory setting on the thermostat, read the “Temperature

Regulation” section in this manual.

CONTAMINATED WATER

This water heater shall not be connected to any heating system(s) or component(s) used with a non-potable water heating appliance.

Toxic chemicals, such as those used for boiler treatment shall not be introduced into this system.

CIRCULATING PUMP

Field installed circulating pumps should be of all bronze construction.

INSULATION BLANKETS

Insulation blankets are available to the general public for external use on electric water heaters but are not necessary with this product. The purpose of an insulation blanket is to reduce the standby heat loss encountered with storage tank heaters. Your water heater meets or exceeds the EPACT and ASHRAE/ IES 90.1 standards with respect to insulation and standby loss requirements, making an insulation blanket unnecessary.

Should you choose to apply an insulation blanket to this heater, you should follow these instructions below. Failure to follow these instructions can result in fire, serious personal injury, or death.

Do not cover the temperature and pressure relief (T & P) valve with an insulation blanket.

Do not cover the instruction manual. Keep it on the side of the water heater or nearby for future reference.

Do obtain new warning and instruction labels for placement on the blanket directly over the existing labels.

TEMPERATURE-PRESSURE RELIEF VALVE

This water heater is provided with a properly rated/sized and certified combination temperature - pressure relief valve by the

10

manufacturer. The valve is certified by a nationally recognized testing laboratory that maintains periodic inspection of production of listed equipment of materials as meeting the requirements for Relief Valves for Hot Water Supply Systems, ANSI Z21.22 • CSA 4.4, and the code requirements of ASME.

If replaced, the new valve must meet the requirements of local codes, but not less than a combination temperature and pressure relief valve rated/sized and certified as indicated in the above paragraph. The new valve must be marked with a maximum set pressure not to exceed the marked hydrostatic working pressure of the water heater (150 psi = 1,035 kPa) and a discharge capacity not less than the water heater Btu/hr or KW input rate as shown on the water heater’s model rating plate.

For safe operation of the water heater, the temperature and pressure relief valve must not be removed from its designated opening nor plugged. The temperature-pressure relief valve must be installed directly into the fitting of the water heater designed for the relief valve. Install discharge piping so that any discharge will exit only within 6 inches (15.2 cm) above, or at any distance below the structural floor. Be certain that no contact is made with any live electrical part. The discharge opening must not be blocked or reduced in size under any circumstances. Excessive length, over 30 feet (9.14 m), or use of more than four elbows can cause restriction and reduce the discharge capacity of the valve.

No valve or other obstruction is to be placed between the relief valve and the tank. Do not connect discharge piping directly to the drain unless a 6” (15.2 cm) air gap is provided. To prevent bodily injury, hazard to life, or property damage, the relief valve must be allowed to discharge water in adequate quantities should circumstances demand. If the discharge pipe is not connected to a drain or other suitable means, the water flow may cause property damage.

The Discharge Pipe:

Shall not be smaller in size than the outlet pipe size of the valve, or have any reducing couplings or other restrictions.

Shall not be plugged or blocked.

Shall be of material listed for hot water distribution.

Shall be installed so as to allow complete drainage of both the temperature-pressure relief valve and the discharge pipe.

Shall terminate at an adequate drain.

Shallnothaveanyvalveorotherobstructionbetweentherelief valve and the drain.

The temperature-pressure relief valve must be manually operated at least once a year. Caution should be taken to ensure that (1) no one is in front of or around the outlet of the temperature-pressure relief valve discharge line, and (2) the water manually discharged will not cause any bodily injury or property damage because the water may be extremely hot. If after manually operating the valve, it fails to completely reset and continues to release water, immediately close the cold water inlet to the water heater, follow the draining instructions in this manual, and replace the temperature-pressure relief valve with a properly rated/sized new one.

If you do not understand these instructions or have any questions regarding the temperature-pressure relief valve call the toll free number listed on the back cover of this manual for technical assistance.

WATER LINE CONNECTIONS

This manual provides detailed piping installation diagrams (see back section of this manual) for typical methods of application. For the heater inlet and outlet connections, di-electric unions are recommended. The water heater may be installed by itself, or with a separate storage tank, on both single and two-temperature systems. When used with a separate storage tank, the circulation may be either by gravity or by means of a circulating pump. When a circulating pump is used it is important to note that the flow rate should be slow so that there will be a minimum of turbulence inside the heater.

CLOSED WATER SYSTEMS

Water supply systems may, because of code requirements or such conditions as high line pressure, among others, have installed devices such as pressure reducing valves, check valves, and back flow preventers. Devices such as these cause the water system to be a closed system.

THERMAL EXPANSION

As water is heated, it expands (thermal expansion). In a closed system the volume of water will grow when it is heated.As the volume ofwatergrowstherewillbeacorrespondingincreaseinwaterpressure due to thermal expansion. Thermal expansion can cause premature tankfailure(leakage).Thistypeoffailureisnotcoveredunderthelimited warranty.Thermal expansion can also cause intermittent temperaturepressure relief valve operation: water discharged from the valve due to excessive pressure build up. This condition is not covered under the limitedwarranty.Thetemperature-pressure relief valve is not intended for the constant relief of thermal expansion.

A properly sized thermal expansion tank should be installed on all closed systems to control the harmful effects of thermal expansion. Contact a local plumbing service agency to have a thermal expansion tank installed.

11

electrical

GENERAL

The installation must conform with these instructions and the local code authority having jurisdiction and the requirements of the power company. In the absence of local codes, the installation must comply with the current editions of the National Electrical Code, NFPA 70 or the Canadian Electrical Code CSA C22.1.

An electrical ground is required to reduce risk of electrical shock or possible electrocution. The water heater should be connected to a separate grounded branch circuit with over-current protection and disconnect switch. The water heater should be grounded in accordance with national and local codes.

Voltage applied to the heater should not vary more than +5% to -10% of the model and rating plate marking for satisfactory operation.

TABLE 310-16. Allowable Ampacities of Insulated Conductors

Not more than three conductors in raceway, cable, or earth (directly buried), based on ambient temperature of 30°C (86°F)

+The load current rating and the overcurrent protection for these conductors shall not exceed 15 amperes for 14 AWG. 20 amperes for 12 AWG. and 30 amperes for 10 AWG copper; or 15 amperes for 12 AWG and 25 amperes for 10 AWG aluminum and copper-clad aluminum.

*For dry locations only. See 75°C column for wet locations.

12

AMPERAGE TABLE/OVERCURRENT PROTECTION

The tables above provides the total connected heating element load in amperes for branch circuit conductor and overcurrent protection sizing. Single-phase heaters are two wire circuits. Three-phase heaters are three wire circuits. In addition to the foregoing, a grounded conductor is required.

Theratingoftheovercurrentprotectionmustbecomputedonthebasis of 125% of the total connected load amperage. Where the standard ratings and settings do not correspond with this computation, the next higher standard rating or setting should be selected.

HEATER CIRCUITS - ELECTRONIC CONTROL MODELS

The water heater’s electrical components are pictured and identified in Figures 1 and 2. The model and rating plate illustration on page 4 identifies heater circuit ratings.The ELECTRONIC CONTROLmodel has two electrical circuits.

The control circuit, which controls the electrical power to heating elements, referring the following control circuit diagram Figure 3.

The power circuit, which is operated by the control circuit carries the electrical load of the heating elements. The following describes the heater circuits and includes wiring diagrams for Delta configuration, refer to the “WYE Configuration Insert” for water heaters operating at 380V/400V/416V/575V. All heater circuits are designed for 50/60 cycle alternating current.

CONTROL CIRCUITELECTRONIC CONTROL MODELS

These models are equipped with an electronic control system. The system includes a CCB (Central Control Board) circuit board, an immersion temperature probe with ECO for temperature sensing and

limiting, a UIM (User Interface Module) for user interface & information display and element current sensors for monitoring the power circuits. Refertothecontrolcircuitlabelonthewaterheaterfordetails.TheCCB ispoweredbyasmall120V/24Vtransformer.Thecontrolcircuitoperates on 120V supplied by a larger 100VA transformer. Standard equipment includes control circuit fusing using two, 3 amp, class G fuses with 600 volt rating. Do not substitute fuses of a different rating.

Sequence of Operation

1.When the control is powered, the UIM should display model information, water temperature, Operating Set Point, heating status and operating mode.

2.If the control determines that the actual water temperature inside thetankisbelowtheprogrammedOperatingSetpointminusthe(1st) differential, a call for heat is activated.

3.Afterallsafetychecksareverified,theCCBwillenergizecontactor coils starting with the lower bank of heating elements (each diagonalrowofthreeheatingelementsisconsidereda“bank”-see Figure1)thenenergizethemiddlebank(ifsoequipped)andtopbank (if so equipped). The middle and top banks (if so equipped) are energized according to programmed 2nd and 3rd differential set points.

4.The control remains in the heating mode until the water temperature reaches the programmed Operating Setpoint. At this point the contactors will be de-energized in the reverse order.

5.The control system now enters the standby operating mode while continuing to monitor the water temperature and the state of other system devices. If the water temperature drops below the programmedOperatingSetpointminusthe(1st)differential,thecontrol will automatically return to step 2 and repeat the heating cycle.

NOTE: See the Electronic Control Models Operation section for more detailed information on temperature settings mentioned above.

120 VAC CONTROL CIRCUIT TRANSFORMER CONNECTIONS - ELECTRONIC CONTROL MODELS

13

A.O. Smith Dve-52, Dve-80, Dve-120 User Manual

WIRING DIAGRAMS

CCB (CENTRAL CONTROL BOARD) CIRCUIT BOARD CONTROL CIRCUIT DIAGRAM - ELECTRONIC CONTROL MODELS

FIGURE 3.

14

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