A.O. Smith DRE, DVE User Manual

Models DRE & DVE - 52/80/120

COMMERCIAL ELECTRIC WATER HEATERS

• INSTALLATION • OPERATION • MAINTENANCE • LIMITED W ARRANTY

CAUTION

TEXT PRINTED OR UNDERLINED IN RED CONTAINS INFORMATION RELATIVE TO YOUR SAFETY. PLEASE READ THOROUGHLY BEFORE A TTEMPTING ANY CONVERSION.

PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND

NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.

PRINTED IN U.S.A. 0906 PART NO. 196674-001

A DIVISION OF A.O. SMITH CORPORATION

MCBEE, SOUTH CAROLINA

www.hotwater.com

Rough-in-Dimensions

Model Number T ank Capacity in Gallons A B Inlet/Outlet

DRE/DVE-52 50 55 1/4 21 3/4 1 1/4 DRE/DVE-80 80 59 1/2 25 1/4 1 1/4

DRE/DVE-120 119 62 1/4 29 1/2 1 1/4

Get to know your water heater

Contents

Page

ROUGH-IN-DIMENSIONS ....................................... 2

GET TO KNOW YOUR WATER HEATER ............... 2

RECOVERY CAP ACITY........................................... 3

APPROVALS............................................................ 3

MODEL AND RATING PLA TE.................................. 4

FOREWORD............................................................ 4

GENRAL SAFETY INFORMA TION.......................... 4

INSTALLATION ........................................................ 5

Required Ability ........................................................ 5

General .................................................................... 5

Location ................................................................... 5

Waterline Connections ............................................. 5

Relief Devices .......................................................... 5-6

Temperature Limiting Control(s) .............................. 6

Temperature Regulation .......................................... 6

PIPING DIAGRAMS ................................................. 7-14

ELECTRICAL

General .................................................................... 14

Branch Circuit .......................................................... 15

Recovery Rating

Page

Amperage Table/Overcurrent Protection ................. 16

Heater Circuits - DVE Models .................................. 16

Control Circuit .......................................................... 16-17

Power Circuit............................................................ 18-21

OPERATION

General .................................................................... 22

Filling........................................................................ 22

Startup...................................................................... 22

High Temperature Limiting Device ........................... 22

Draining.................................................................... 22

Circulating Pump ..................................................... 22

MAINTENANCE

General .................................................................... 23

Flushing ................................................................... 23

Sediment Removal ................................................... 23

Lime Scale Removal ................................................ 23-24

Checklist .................................................................. 24

Replacement Parts .................................................. 24

LEAKAGE CHECKPOINTS ..................................... 25

LIMITED WARRANTY.............................................. 26

RECOVERY RATE IN GALLONS PER HOUR*

Temperature Rise °F

Standard BTU/

Models KW Input Hour 30° 40° 50° 60° 70° 80° 90° 100° 110° 120° 130° 140°

DRE/DVE 6 20,478 82 62 49 41 35 31 27 25 22 21 19 18 DRE/DVE 9 30,717 123 92 74 62 53 46 41 37 34 31 28 26 DRE/DVE 12 40,956 164 123 98 82 70 61 55 49 45 41 38 35 DRE/DVE 13.5 46,075 184 138 111 92 79 69 62 55 50 46 43 40 DRE/DVE 15 51,195 205 154 123 102 88 77 68 61 56 51 47 44 DRE/DVE 18 61,434 246 184 148 123 105 92 82 74 67 61 57 53 DRE/DVE 24 81,912 328 246 197 164 140 123 109 98 89 82 76 70 DRE/DVE 27 92,151 369 276 221 184 158 138 123 111 101 92 85 79 DRE/DVE 30 102,390 410 307 246 205 176 154 137 123 112 102 95 88 DRE/DVE 36 122,868 492 369 295 246 211 184 164 148 134 123 113 105 DRE/DVE 40.5 138,226 554 418 3332 277 237 208 185 166 151 138 128 119 DRE/DVE 45 153,585 615 461 369 307 263 230 205 184 168 154 142 132 DRE/DVE 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.

Approvals

All models bear the All models are listed National Sanitation by Underwriters Foundation seal of Laboratories Inc. approval.

Model and Rating

Foreword

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 WA TER PIPING AND THE ELECTRICAL WIRING BE INST ALLED AND CONNECTED AS 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.

In addition to these instructions, the equipment shall be installed in accordance with those installation regulations in force in the local area where the installation is to be made. Authorities having

General Safety Information

PRECAUTIONS

DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN UNDER WATER. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control 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 SERVICEMAN.

1. EXTERNAL FIRE.

2. DAMAGE.

3. FIRING WITHOUT WATER.

GROUNDING INSTRUCTIONS

This water heater must be grounded in accordance with the National Electric Code and/or local codes. These must be followed in all cases.

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)

CAUTION

HYDROGEN GAS CAN BE PRODUCED IN A HOT WATER SYSTEM SERVED BY THIS HEA TER THA T HAS NOT BEEN USED FOR A LONG PERIOD OF TIME (GENERALLY TWO WEEKS OR MORE).

reduce the risk of injury under these conditions, it is recommended

HYDROGEN GAS IS EXTREMELY FLAMMABLE. To

jurisdiction shall be consulted before installations are made.

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.

ALWAYS USE THE CORRECT SIZE FOR THE CIRCUIT. SEE P AGE 16 THROUGH 21.

The principal components of the heater are identified on page 2. The model and rating plate on page 4 interprets cert ain markings into useful information. Both of these references should be used to identify the heater, its components and optional equipment.

that the hot water faucet be opened for several minutes at the kitchen sink before using any electrical appliance connected to the hot water system. If hydrogen is present there will probably be an unusual sound such as air escaping through the pipe as the water begins to flow.

THERE SHOULD BE NO SMOKING OR OPEN FLAME NEAR

THE F AUCET AT THE TIME IT IS OPEN.

WHEN REPLACING FUSES

INSULA TION BLANKETS

Insulation blankets available to the general public for external use on water heaters are not approved for use on your A.O. Smith water heater. The purpose of an insulation blanket is to reduce the standby heat loss encountered with storage tank water heaters. Your A.O. Smith water heater meets or exceeds the ASHRAE/IES 90.1b 1992 standards with respect to insulation and standby loss requirements, making an insulation blanket unnecessary.

WARNING

Should you choose to apply an insulation blanket to this heater, you should follow these instructions (See "Getting to know your water heater" on page 2 for identification of components mentioned below). Failure to follow these instructions can result in fire, asphyxiation, serious personal injury or death.

Do not cover the temperature & pressure relief valve.

•

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

• Do obtain new labels from A.O. Smith for placement on the blanket directly over the existing labels.

WARNING FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN SERIOUS PERSONAL INJUR Y OR DEATH.

Installation

REQUIRED ABILITY

INSTALLATION OR SERVICE OF THIS WATER HEATER REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD INVOLVED. PLUMBING AND ELECTRICAL WORK ARE INVOLVED.

GENERAL

The installation must conform to these instructions and the local code authority having jurisdiction. Grounding and electrical wiring connected to the water heater must also conform to the current version of the requirements the current version of the CAN/CSA-C22.2 No. M91. These codes may be obtained from the following institutes; The NFP A-70 is available from the National Fire Protection Association, 1 Batterymarch Park, Quincy, MA

02269. The CAN/CSA C22.2 No. M91 is available from the Canadian Standards Association, 178 Rexdale Blvd., Toronto Ontario, Canada M9W 1R3.

If your location requires the installation of the water heater to comply with National Sanitation Foundation requirements, the heater must be sealed to the floor so as to prevent seepage underneath the heater. The following are recommended sealants that may be used on all types of flooring except concrete GE Silicone Seal RTV-120, 103, 108, and 109.

National Electrical Code NFPA-70 or for Canadian

Canadian Electric Code,

LOCATION

For proper installation, the heater should be installed on a level surface.

LOCATE THE WATER HEATER NEAR A FLOOR DRAIN. THE HEATER SHOULD BE LOCATED IN AN AREA WHERE LEAKAGE FROM THE HEA TER OR CONNECTIONS WILL NOT RESULT IN DAMAGE TO THE ADJACENT AREA OR TO LOWER FLOORS OF THE STRUCTURE.

WHEN SUCH LOCATIONS CANNOT BE A VOIDED, A SUITABLE DRAIN PAN SHOULD BE INSTALLED UNDER THE HEATER. Such pans should be fabricated with sides at least 2" deep, with length and width at least 2" greater than the diameter of the heater and must be piped to an adequate drain. Drain pans suitable for these heaters are available from your distributor or Product Service Division, A.O. Smith W ater Heater Parts Fulfillment, 125 Southeast Parkway, Franklin, TN 37068.

Water heater life depends upon water quality , water pressure and the environment in which the water heater is installed. Water heaters are sometimes installed in locations where leakage may result in property damage, even with the use of a drain pan piped to a drain. However, unanticipated damage can be reduced or prevented by a leak detector or water shut-off device used in conjunction with a piped drain pan. These devices are available from some plumbing supply wholesalers and retailers, and detect and react to leakage in various ways:

• Sensors mounted in the drain pan that trigger an alarm or turn off the incoming water to the water heater when leakage is detected.

• Sensors mounted in the drain pan that turn off the water supply to the entire home when water is detected in the drain pan.

• Water supply shut-off devices that activate based on the water pressure differential between the cold water and hot water pipes connected to the water heater.

• Devices that will turn off the gas supply to a gas water heater while at the same time shutting off its water supply.

Locate the heater close to the point of major hot water usage and the power supply.

• Try to make hot water piping and branch circuit wiring as short as possible.

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

THE HEATER SHOULD NOT BE LOCA TED IN AN AREA WHERE IT WILL BE SUBJECT TO FREEZING.

Suggested clearances from adjacent surfaces are 18 inches in front for access to the controls and elements and 12 inches from top. The heater may be installed on or against combustible surfaces.

W ATER LINE CONNECTIONS

This manual provides detailed installation diagrams (see back section of this manual) for typical methods of application for the water heaters. 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.

CAUTION

A closed system will exist if a check valve, pressure reducing valve, or a water meter is installed in the cold water line between the water heater and street main (or well).

Excessive pressure may develop causing premature tank failure or intermittent relief valve operation. This type of failure is not covered by the limited warranty. An expansion tank may be required in the inlet supply line between the appliance and the meter or valve to compensate for the thermal expansion of water.

If a water heater is installed in a closed water system, contact the water supplier or local plumbing inspector on how to control this situation.

RELIEF DEVICES

CAUTION

TO REDUCE THE RISK OF EXCESSIVE PRESSURES AND TEMPERATURE IN THIS WATER HEATER, INSTALL TEMPERATURE AND PRESSURE PROTECTIVE EQUIPMENT REQUIRED BY LOCAL CODES but not less than a combination

temperature and pressure relief valve certified by a nationally recognized testing laboratory that maintains periodic inspection of production of listed equipment or materials, as meeting the requirements for Relief Valves for Hot Water Supply Systems, ANSI Z21.22 /CSA 4.4 (current version).

This valve must be marked with a maximum set pressure not to exceed the marked maximum working pressure of the water heater.

INSTALL THE VALVE INTO AN OPENING PROVIDED AND MARKED FOR THIS PURPOSE IN THE WATER HEATER, AND ORIENT IT OR PROVIDE TUBING SO THAT ANY DISCHARGE FROM THE VAL VE WILL EXIST ONL Y WITHIN 6 INCHES ABOVE, OR A T ANY DISTANCE BELOW THE STRUCTURAL FLOOR AND CANNOT CONTACT ANY LIVE ELECTRICAL PART. THIS DISCHARGE OPENING MUST NOT BE BLOCKED OR REDUCED IN SIZE UNDER ANY CIRCUMST ANCES.

The pressure setting of the relief valve should not exceed the pressure capacity of any component in the system. The temperature setting of the relief valve should not exceed 210°F.

SMALL CHILDREN TO USE A HOT WATER TAP, OR TO DRAW THEIR OWN BATH WATER. NEVER LEAVE A CHILD OR DISABLED PERSON UNA TTENDED IN A BATHTUB OR SHOWER.

An unplugged 3/4" relief valve opening is provided for installing temperature and pressure relief valve.

TEMPERA TURE LIMITING CONTROL(S)

Both the DVE and DRE model water heaters incorporate high temperature cutoffs. In the event of high temperature cutoff operation, the reason for the operation of the high temperature cutoff operation must be determined and corrected. Once the situation has been corrected the high temperature cutoff(s) may be reset in the following manner:

DVE Models

The DVE models have a single immersion-type high temperature cutoff control in the control circuit, see DVE CONTROL CIRCUIT DIAGRAMS. This high temperature cutoff is factory set to open at 190°F (88°C). To manually reset the control you must:

1. Disconnect the power to the heater.

2. Allow the tank to cool to approximately 120°F.

3. Remove the front control cover.

4. Press the manual reset button. The control will not reset until it has cooled approximately 50°F (28°C).

DRE Models

The DRE models have multiple surface mounted combination high temperature cutoff and thermostat controls. There is one of these combination high temperature cutoff and thermostat controls for each element in a DRE model, see DRE CIRCUIT DIAGRAMS. Each of the high temperature controls is of the manual reset type. To manually reset the controls:

THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO SET TEMPERATURES.

SETTING THE WATER HEATER TEMPERATURES AT 120°F WILL REDUCE THE RISK OF SCALDS. Some states require settings at specific lower temperatures.

The water temperature is controlled in the DVE models with a single thermostat located on the right front of the heater, just inside the control cabinet. This control is set at 140°F at the factory and has a fixed 5°F differential. The DRE models have multiple thermostats depending on the configuration purchased. These thermostats are also set at 140°F and have a 5-15°F differential. A.O. Smith recommends setting the dial at the lowest setting which produces an acceptable hot water supply. This will always give the most energy efficient operation.

Figure 1 shows the approximate time-to-burn relationship for normal adult skin.

Valves for reducing point-of-use temperature by mixing cold and hot water are available. Also available are inexpensive devices that attach to faucets to limit hot water temperatures. licensed plumber or the local plumbing authority.

Contact a

1. Disconnect the power to the heater.

2. Allow the tank to cool approximately 160°F.

3. Remove the front control cover.

4. Press the manual reset button on each of the effected controls. The control will not reset until it has cooled approximately 30°F (17°C).

Once the control(s) has been reset the control cover should be replaced prior to operating the heater.

TEMPERA TURE REGULA TION

DANGER

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 TEMPERA TURE A T WHICH INJURY OCCURS V ARIES WITH THE PERSONS AGE AND TIME OF EXPOSURE. THE SLOWER RESPONSE TIME OF CHILDREN, AGED, OR DISABLED PERSONS INCREASES THE HAZARDS TO THEM. NEVER ALLOW

DRE MODELS DVE MODELS

Temperature Time to produce 2nd & 3rd

Setting Degree burns on adult skin

180°F Nearly instantaneous 170°F Nearly instantaneous 160°F About 1/2 second 150°F About 1-1/2 seconds 140°F Less than 5 seconds 130°F About 30 seconds 120°F More than 5 minutes

FIGURE 1

Piping Diagrams

ONE TEMPERA TURE WITH CIRCULATING LOOP

INSERT B

VACUUM RELIEF

VALVE. INSTALL PER

LOCAL CODES.

DANGER

TEMPERATURE SETTING SHOULD NOT EXCEED SAFE TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE CONTROL WARNING ON PAGE 6. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.

CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACKFLOW PREVENTER, CHECK VALVE OR WATER METER WITH CHECK VALVE. PROVISIONS FOR THERMAL EXPANSION OF WATER IN THE HOT WATER SYSTEM MUST BE PROVIDED.

*PIPE TO OPEN DRAIN INSTALL IN ACCORDANCE WITH A LL LOCAL CODES.

INSERT B

V ACUUM RELIEF

V ALVE. INSTALL PER

LOCAL CODES.

DANGER

TEMPERATURE SETTING SHOULD NOT EXCEED SAFE TEMPERATURE A T FIXTURES. SEE WATER TEMPERATURE CONTROL WARNING ON PAGE 6. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.

INSERT B

V ACUUM RELIEF

V ALVE. INSTALL PER

LOCAL CODES.

DANGER

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