A.O. Smith DURA-Power DRE-52 User manual

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FOR INSTALLATION BY QUALIFIED SERVICE PERSONNEL ONLY
CONVERSION KIT INSTRUCTIONS
Models DRE & DVE 52, 80, & 120
Commercial Electric Water Heaters
Series 100
CAUTION
TEXT PRINTED OR OUTLINED IN RED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY.
PLEASE READ THOROUGHLY BEFORE
ATTEMPTING ANY CONVERSION. 500 Tennessee Waltz Parkway
Ashland City, TN 37015
1-800-433-2545
www.hotwater.com
PRINTED IN U.S.A. 1008 196678-002

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FOREWORD
The purpose of this manual is to explain how to change the voltage and wattage of your commercial electric water heater
by changing the elements. This manual is not intended to explain the rebuilding of commercial electric water heaters
in the eld.
Addition of heating elements or subtraction of heating elements in the eld is not approved by Underwriters Laboratories,
Inc., and therefore, is not allowed and should not be attempted.
Please note the limitation that “both the heater required and the heater to be converted must be found on the same
page” (in this manual) must be followed. Before attempting any conversion read the detailed instructions contained on
pages 8, 9, 10 and 11.
SAFETY
Be sure to disconnect appliance from electrical supply before working on or near the electrical system of the heater.
Never touch electrical components with wet hands or when standing in water.
REQUIRED ABILITY
CONVERSION OF ANY WATER HEATER LISTED IN THIS MANUAL REQUIRES ABILITY EQUIVALENT
TO THAT OF A LICENSED ELECTRICAL TRADESMAN.
CONVERSION MATERIALS
1. Screw Plug Element Remover: Part no. 9000429015 or 1-1/2” deep well socket and ratchet.
2. Screwdrivers: Two required, one #2 phillips and one slotted screwdriver.
3. Conversion kit: Includes conversion instructions, replacement electrical elements, conversion kit label, and caution
label.
4. Thread sealer: When replacing screw-in type elements, be sure to use Dow Corning®silicone sealant (bathtub sealer)
on threads.
TABLE OF CONTENTS
KW Conversion (Element Replacement)............. 4
Voltage Conversion ............................................. 4-5
Phase Conversion ............................................... 5-6
Caution ................................................................ 6
Final Assembly .................................................... 6-7
Check List............................................................ 7
Miscellaneous Information................................... 7-8
Foreword ............................................................... 2
Conversion Materials............................................. 2
Conversion Guidelines ....................................... 3
Conversion Instructions
Introduction.......................................................... 4
Heater Preparation .............................................. 4
Page Page

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CONVERSION GUIDELINES
Be sure to read and understand the conversion limitations and instructions prior to conversion.
1. No addition or substraction of heating elements are allowed in the conversion process;
2. Conversion kits are designed for specic voltage with Delta conguration, no other conguration or voltage is
allowed;
3. Refer to “Branch Circuit Section” in User’s Manual for electrical specications;
4. Check all water and electrical connections for tightness after conversion.
TO USE THE TABLE:
1. Find the element number of the heater that you wish to convert.
2. Find the total kilowattage under “Desired Input” column, then move across the Table on same line to voltage
desired. The kit number required for the conversion will be the one where the desired KW row intersects the voltage
column.
3. Order the appropriate kit number.
4. Follow the conversion instructions detailed on pages 9 through 13 to complete conversion.
5. Fill out the check list on Page 12 after completing the unit conversion.
CONVERSION KIT NUMBER TABLE
Models Allowed
For Conversion Desired Input Conversion Kit No. At Desired Voltage
Total kW Element kW 208V 240V 277V 480V
DVE/DRE
52,80,120
with
3Elements
6 2 9005587105 9005600105 9005615105 9005621105
9 3 9005588105 9005601105 9005616105** 9005622105
12 49005589105 9005602105 9005617105 9005623105
13.5 4.5 9005585105 9005597105 9005612105** 9005618105
15 59005586105 9005598105 9005613105** 9005619105
18 6N/A 9005599105 9005614105 9005620105
DVE/DRE
52, 80, 120
with
6Elements
18 39005592105 9005606105 9005627105** 9005632105
24 49005593105 9005607105 9005628105 9005633105
27 4.5 9005590105 9005603105 9005624105** 9005629105
30 59005591105 9005604105 9005625105** 9005630105
36 6N/A 9005605105 9005626105 9005631105
DRE 80, 120
DVE 52, 80, 120
with
9Elements
36 49005596105 9005611105 9005637105 9005641105
40.5 4.5 9005594105 9005608105 9005634105** 9005638105
45 59005595105 9005609105 9005635105** 9005639105
54 6N/A 9005610105 9005636105 9005640105
* No conversion kits available for 50 gallon capacity 9 element models equipped with surface-mounted thermostat.
** Indicates the conversion kit with Incoloy Elements.

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CONVERSION INSTRUCTIONS
REQUIRED ABILITY
CONVERSION OF ANY WATER HEATER LISTED IN THIS MANUAL REQUIRES ABILITY EQUIVALENT
TO THAT OF A LICENSED ELECTRICAL TRADESMAN
I. INTRODUCTION
Satisfying a customer order for a commercial electric heater from inventory may require modication to the KW input,
the voltage, or the phase. Conversions may involve revision to 1, 2, or all 3 of these electrical characteristics.
II. HEATER PREPARATION
The heater should be placed in a well lit area. Complete removal of the shipping crate is not required. The front of the
heater with the control box will be visible through the clear plastic. Cut a 3-sided ap into the plastic, cut should be on
top, bottom and right side approximately 4” from the wooden edge.
Release the two control panel screws on the water heater door.
To expose elements, remove the foam door inside the control panel.
Remove the T & P valve (separate package).
III. KW CONVERSION (ELEMENT REPLACEMENT)
A. Remove wires from one element at a time. It is not necessary to tag loose wires as the wiring schematic is
inside the control panel door.
B. Remove element from heater using part no. 9000429015 or 1-1/2” deep well socket and ratchet. Return the
elements to appropriate storage bin.
C. Open the appropriate conversion kit and remove the elements. Check each element to ensure correct voltage
and wattage.
D. Install the new element, starting it by hand. Anew “O” ring gasket should be installed on each element. Element
threads should be lubricated with Dow Corning® silicon sealant (or equal). Screw element into tting until it
seats. Tighten 1/2 to 3/4 turn with wrench.
E. Rewire the element as directed on wiring schematic, located inside control panel door. Screw terminals must be
snug, however, caution must be exercised. Overtightening may break the terminal block, requiring replacement
of the element.
F. Repeat steps A thru E for all other elements being replaced.
IV. VOLTAGE CONVERSION
A. Surface thermostat models merely require installation of the appropriate elements to accomplish a change in
voltage. See KW conversion step III.
B. Immersion thermostat models require installation of the appropriate elements AND may also require a
transformer tap change. Immersion thermostat models are equipped with a transformer having 5 connections:
common, 208, 240, 277 and 408 and 2 secondary connections. See the following diagrams.
Only one wire need be changed on the transformer to change voltage. Remove the wire from the terminal
marked 208, 240, 277 or 480 and attach it to the appropriate terminal marked 208, 240, 277 or 480.
C. Do not change the common connections or the secondary wire connections.

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V. PHASE CONVERSION
A. IMMERSION THERMOSTAT MODEL
THREE PHASE TO SINGLE PHASE
1. Disconnect blue wires and yellow wires from terminal L-3.
2. Connect all blue wires to terminal L-1 (with black wires).
3. Connect all yellow wires to terminal L-2 (with red wires).
4. Incoming power will be connected to
terminals L-1 and L-2 at job site.
B. IMMERSION THERMOSTAT MODEL
SINGLE PHASE TO THREE PHASE
1. Disconnect blue wires from terminal L-1.
2. Disconnect yellow wires from terminal L-2.
3. Connect all blue wires and yellow wires to terminal L-3.
4. Incoming power will be connected to terminals
L-1, L-2 and L-3 at job site.
IMMERSION THERMOSTAT MODEL TRANSFORMER
IMMERSION THERMOSTAT MODEL
SINGLE PHASE TERMINAL BLOCK
IMMERSION THERMOSTAT MODEL
THREE PHASE TERMINAL BLOCK
IMMERSION THERMOSTAT MODEL TRANSFORMER
CONNECTION TABLES
Volts Line On Load on
208 Common & 208
240 Common & 240 Secondary
277 Common & 277 120V
480 Common & 480
480 277 240 208
COM

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C. SURFACE THERMOSTAT MODEL
THREE PHASE TO SINGLE PHASE
1. Disconnect blue wires from terminal L-2.
2. Connect all blue wires to terminal L-1
(with black wires).
3. Disconnect all red wires from terminal L-3.
4. Connect all red wires to terminal L-2 (with yellow wires).
5. Incoming power will be connected to
terminals L-1 and L-2 at job site.
D. SURFACE THERMOSTAT MODEL
SINGLE PHASE TO THREE PHASE
1. Disconnect blue wires from terminal L-1
2. Disconnect red wires from terminal L-2.
3. Connect all blue wires to terminal L-2 (with yellow wires).
4. Connect red wires to terminal L-3.
5. Incoming power will be connected to
terminals L-1, L-2 and L-3 at job site.
VI. CAUTION
Recheck all terminals for tightness, proper wiring per schematic, and neatness of wiring, Heater should
be no less than factory constructed quality and appearance.
CHECK ALL WATER AND ELECTRICAL CONNECTIONS FOR TIGHTNESS
VII. FINAL ASSEMBLY
A. CONTROL PANEL
Replace foam door. Cover all elements
and thermostats as originally constructed.
Replace T & P valve package, close door,
relatch and tighten the two control panel screws.
B. RATING PLATE MODIFICATION
Following is a sample of the standard rating
plate supplied on the front of the control panel
door.
SURFACE THERMOSTAT MODEL
SINGLE PHASE TERMINAL BLOCK
SURFACE THERMOSTAT MODEL
THREE PHASE TERMINAL BLOCK
SAMPLE RATING PLATE

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The voltage, element KW, total KW data of the rating plate must be modied by covering them with the label provided in
the conversion kit. Be sure the new ratings on the label match the conversion you have just completed.
Peel off the back of the label and paste over the four lines as shown on the revised rating plate below.
C. Peel off back of caution label and attach label to upper right hand corner of control panel door.
D. CRATE IDENTIFICATION
Using a black magic marker, cross out heater identication on crate as appropriate. In bold letters, write
new electrical specications in crate, matching those on the revised rating plate.
E. SHIPPING CRATE
Close and tape the plastic ap on front of crate.
CHECK LIST
 All affected parts have been installed properly and have been checked for tightness.
 All affected wires have been checked for tightness.
 New elements have been wired per wiring diagram label on the unit.
 New elements have been tightened properly.
 New elements have been leak checked.
 New rating plate overlay has been installed properly over the existing rating plate.
VIII. MISCELLANEOUS INFORMATION.
A. NON STANDARD CONSTRUCTION
At 480 and 240 volts, 18KW is normally supplied using three 6,000 watt elements. They can however, be
constructed using six 3,000 watt elements.
At 480 volts and 240 volts, 36KW is normally supplied using six 6,000 watt elements. It can however, be supplied
using nine 4,000 watt elements.
SAMPLE RATING PLATE WITH CONVERSION LABEL

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B. ELEMENT SIZE VERIFICATION
All elements are marked with both wattage and voltage. Verication can be made by measuring the ohms
resistance across the terminals of the elements. Element must be disconnected from the circuit. The following
table gives resistance in ohms for all elements used in commercial electric water heaters.
Element ohms resistance should be within ±5% of the above values.
Examples: Elements with an ohm resistance of 14 ohms indicates that it is either a 3,000 watt/208 volt element
and/or a 4,000 watt/240 volt element (dual rated type).
CAUTION
NEVER OPERATE THE HEATER WITHOUT FILLING WITH WATER PER THE FILLING INSTRUCTIONS. FAILURE
TO DO SO WILL DAMAGE INTERNAL PARTS.
OHMS RESISTANCE TABLE
VOLTAGE
WATTAGE 208 240 480
2000 21.63 28.80 115.20
3000 14.42 19.20 76.80
4000 10.82 14.40 57.60
4500 9.61 12.80 51.20
5000 8.65 11.52 46.08
6000 7.21 9.60 38.40
Number KW Single (1) phase Three (3) Phase
KW of Each
Input Elements Elements 208V 240V 480V 208V 240V 480V
6 2.0 28.8 25.0 12.5 16.7 14.4 7.2
9 3.0 43.3 37.5 18.8 25.0 21.7 10.8
12 4.0 57.7 50.0 25.0 33.3 28.9 14.4
13.5 4.5 64.9 56.3 28.1 37.5 32.5 16.2
15 5.0 72.1 62.5 31.3 41.6 36.1 18..0
18 6.0 - - - - 75.0 37.5 - - - - 43.3 21.7
18 3.0 86.5 - - - - - - - - 50.0 - - - - - - - -
24 4.0 115.4 100.0 50.0 66.6 57.7 18.9
27 4.5 129.8 112.5 56.3 74.9 65.0 32.5
30 5.0 144.2 125.0 62.5 83.3 72.2 36.1
36 6.0 - - - - 150.0 75.0 - - - - 86.6 43.3
36 4.0 173.1 - - - - - - - - 99.9 - - - - - - - -
40.5 4.5 194.7 168.8 84.4 112.4 97.4 48.7
45 5.0 216.3 187.5 93.8 124.9 108.3 54.1
54 6.0 - - - - 225.0 112.5 - - - - 129.9 65.0
3
6
9
FULL LOAD CURRENT IN AMPERES

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NOTES

500 Tennessee Waltz Parkway
Ashland City, TN 37015
1-800-433-2545
www.hotwater.com