State Water Heaters RESIDENTIAL ELECTRIC WATER HEATER How to use

RESIDENTIAL ELECTRIC WATER HEATER
SERVICE HANDBOOK
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Technical Training Department 1 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
TABLE OF CONTENTS
Page
Introduction
Certification and Approval…………………1
Tools ......................................................... 2
Terms, Definitions, Formulas..................... 2
Residential Electric Water Heaters
Installation.................................................. 4
Construction............................................... 7
Element Test - continuity ........................... 8
Element Test - grounded ........................... 9
Element Test - amperage ........................ 10
Field Wiring.............................................. 12
Thermostats............................................. 13
C-2 Circuit & Sequence of Operation ...... 14
C-2 Circuit Testing ................................... 15
A-6 Circuit and Wiring.............................. 16
A-6 Sequence of Operation ..................... 17
Page
A-9 Off Peak Circuit...........................18
A-9 Circuit Sequence of Oper............19
Three phase unbalanced circuit ........20
A-9 Circuit Testing .............................21
Miscellaneous Information.................24
Service Bulletins 25
RESIDENTIAL ELECTRIC HANDBOOK INTRODUCTION
This service handbook is designed to aid in servicing and troubleshooting Residential
Electric water heaters in the field. No duplication or reproduction of this book may be made
without the express written authorization of the manufacturer.
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 commonly faced
situations encountered in the operation of the Residential Electric product line and is not
meant to be all-inclusive. If you are experiencing a problem not covered in this
handbook, please contact the Information Center at 1-800-365-0024 or your local
distributor for further assistance. This handbook is intended for use by licensed
plumbing professionals and reference should be made to the instructional manual
accompanying the product.
Code Compliance - All models meet or exceed federal minimum energy standards
effective January 20, 2004, according to latest editions of the National Appliance Energy
Conservation Act (NAECA). They also comply with the latest editions of the B.O.C.A.
National Codes, C.E.C., U.B.C., S.B.C.C., C.A.B.O. and the H.U.D. standards. All
models U.L. Listed according to safety specifications outlined in Underwriters'
Laboratories, Inc. Standards for Safety (U.L. 174).
CERTIFICATIONS AND APPROVALS

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Technical Training Department 2 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
TOOLS REQUIRED:
FOR SERVICING RESIDENTIAL ELECTRIC MODELS
•#2 Phillips screw driver
•electrical multi-meter (volt/Ohm)
•water pressure gauge (with a lazy hand)
•thermometer
•hose – to drain tank
•container – to measure gallons per minute flow
•1 1/16 inch – 6 point – socket (for anode removal)
•1 ½ inch deep socket or a manufacturer’s element wrench
•Amp meter- clamp type
TERMS, DEFINITIONS, AND FORMULAS:
Draw efficiency is the quantity of hot water available to the consumer before the outlet water
temperature decreases 25 degrees F. A 40 gallon water heater will typically provide 70% (28
gallons) of this “usable” hot water. The burner or elements are allowed to operate during this
test. Incoming, cold water mixes the remaining stored water below this 25 degree limitation.
Energy Factor is an indicator of the combined thermal efficiency and standby efficiency of a
water heater. The higher the energy factor, the more efficient the water heater will be.
Recovery rate is the amount of water that is heated to a set temperature, per hour. An
example might be that a water heater has a recovery rate of 30 gallons of water per hour at 80
degree F. (Fahrenheit) temperature rise.
Temperature rise is the increase in the temperature from its coldest “inlet” water temperature
to the desired hot (outlet) setting. Typically this is assumed to be 40 degrees entering water;
120 degrees desired stored water or 80 degrees “temperature rise.”
Standby efficiency is the water heater’s ability to contain heat in the tank. A minimum of tank
water heat loss per hour is desired.
Water (for all practical purposes) cannot be compressed.
GENERAL SECTION

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Technical Training Department 3 of 36 Residential Electric Svc Handbook
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GENERAL SECTION – cont’d.
TERMS, DEFINITIONS, AND FORMULAS:
Water Expands when it is heated. Volume increases about 2% from 40° to 140° F.
Minerals and gases will separate from water as temperature increases
Amperage (Amps) (1 phase) = Watts divided by Volts (Ohm’s Law)
KW Required = (GPH X 8.25 X Temp. Rise X 1.0) divided by (3413)
Ohms = Volts divided by Amperes (Ohm’s Law)
One kilowatt is equal to 1000 watts
One kilowatt is equal to 3,413 BTU
Recovery Rate = (KW X 3413) divided by (Temp. Rise X 8.25)
Rise (F°) = (KW X 3413) divided by (GPH X 8.25)
Supply electrical fusing or breakers should be sized at least 125% of expected heater
amperage.
Water weighs 8.25 pounds per gallon at 120°F (49°C).
% of Hot water = (Mixed temp. – Cold) divided by (Hot temp. – Cold). This formula
gives the number of gallons drawn from the water heater for each gallon delivered at a
shower head or faucet. If the shower head flow rate (gallons per minute) is known, the
draw efficiency and gallon capacity of the water heater may be used to calculate the
length of the showering period in minutes.
Watt Density = the density of the wattage output of the element compared to the surface area
of the element (i.e. “High Watt Density Element” will have the most wattage per square inch of
element surface
Energy Factor:
Formula: The minimum EF allowed = .97 - .0019 x V (volume of storage)
Example: Volume (50 gal.) x .0019 = .095 gal.x.97 - .095 = .875 (minimum energy factor).
Note: Since the formula varies by volume, each tank size will have a different minimum
energy factor requirement.
The formula for gas water heaters is different than the above example.

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Technical Training Department 4 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
SOME MODELS MAY HAVE SIDE OR REAR CONNECTIONS
INSTALLATION - typical
INSTALLATION MUST FOLLOW LOCAL CODES AND INSTRUCTION MANUAL GUIDELINES.
TO FUSED
ELECTRICAL
SUPPLY
(BREAKER BOX)
COLD WATER
INLET LINE
SHUTOFF
VALVE
INSTALL THERMAL
EXPANSION TANK AFTER
SHUT OFF VALVE. PRE-
PRESSURIZED TO EQUAL
SUPPLY WATER
PRESSURE
DRAIN LINE
HOT WATER
TO FIXTURES
ELECTRICAL
JUNCTION BOX
ADJACENT
CONDUIT
ENTRANCE
RATING PLATE
WITH MODEL
AND SERIAL
NUMBER
TEMPERATURE AND
PRESSURE RELIEF VALVE
OPENING MAY BE ON SIDE
OR TOP OF HEATER. DO
NOT REUSE OLD VALVE
ACCESS PANELS – WATER
TEMPERATURE ADJUSTMENT
IS BEHIND THESE PANELS.
RECOMMENDED SETTING IS
125 °
SEE MANUAL
AND LABELS FOR
INSTALLATION
CLEARANCES
†FUSE SHOULD BE RATED
AT AMPERAGE INDICATED
ON RATING PLATE TIMES
125%
UNION
FLOOR
DRAIN
6” AIR GAP (LOCAL
CODES VARY)
UNION
DRAIN VALVE
INSTALL DRAIN PAN TO PREVENT
FUTURE WATER DAMAGE.

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Technical Training Department 5 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
INSTALLATION - typical
Parallel Piping arrangement for multiple water heaters
ensures maximum hot water and efficient operation.
This piping arrangement
depends on dividing piping
between water heaters evenly.
It may be expanded for more
than two water heaters. Pipe
size may need to increase if
more water heaters are added
to improve water flow for larger
applications.
This balanced piping system is
preferred instead of a series
piping system where one water
heater feeds heated water to
the cold inlet of the second
water heater. A series
arrangement does not deliver
hot water as quickly or in as
great an amount as a parallel
piping arrangement.
Expansion tanks may be
required by local code. Water
expands by about 2% of its
volume as it is heated from
40°F. to 140°F. The
expansion created in a 40
gallon water heater would be
about 8/10 of a gallon.
A 2 gallon expansion tank will
absorb this amount of
expansion. For larger
applications consult the tank
manufacturers sizing
information.

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Technical Training Department 6 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
CONSTRUCTION - typical
This portion of this manual applies to the Operation and Servicing of Residential Electric,
Tank Type, Water Heaters. The illustrations are for two element models but the
information also applies to single element models.
Model and
Rating Plate

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Technical Training Department 7 of 36 Residential Electric Svc Handbook
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Construction – cont’d.
Heating element(s)
This style water heater will have
one or two electric, heating
elements immersed in the tank.
One element will always be
located low in the tank; a second
element is commonly located
down about 1/3 of the tank height from the top of the tank. These elements will not
operate at the same time unless the water heater was ordered with a simultaneous
wiring system. If they operate at the same time, amperage draw doubles, wire gauge
size increases, fuse size increases and little is gained in heat recovery.
Residential Electric – continued
Since the element’s heating area is totally immersed in the tank, thermal efficiency is assumed
to be 100%. All of the heat generated by the element enters the water.
Watt Density = the density of the wattage output of the element compared to the surface area
of the element (i.e. “High Watt Density Element” will have the most wattage per square inch of
element surface. If the above elements generated 4,500 w. each, “A” might be considered a
“high” watt density element, “B” a medium and “C” a low.)
C.
A.
B.

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Technical Training Department 8 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
ELEMENT TEST – RESISTANCE/CONTINUITY
OHMS Resistance Check**
Disconnect wires from the element terminals.
NOTE: OHM readings may vary by up to
7.5% depending on the meter and the
element. Always check meter for proper
operation by touching probe ends together.
Test Conditions:
This test uses the multi-meter's battery as the
electrical supply.
Procedures:
Power to the water heater is "OFF".
Multi-meter set to OHMS scale testing.
Black lead "Common" port.
Red lead in "Ω" or “OHMS" port.
Dial indicator set to scale above expected indication.
Note: Volts divided by Amps = OHMS
Example: 240V. ÷ 18.75 Amps = 12.8 OHMS
Continuity Check**
Same as above but with meter set to continuity scale.
If the meter has an audible indicator, listen for sound..
Test probe on each terminal of an element
Resistance of Element in Ohms (± 7.5%)
Rated WattageRated
Voltage 600 750 1000 1250 1500 2000 2500
120 23.2 18.6 13.9 11.1 9.28 6.96 5.57
208 72.1 57.7 43.3 34.6 28.8 21.6 17.3
240 92.8 74.3 55.7 44.6 37.1 27.8 22.3
277 128 102 76.7 61.4 51.2 38.4 30.7
Rated WattageRated
Voltage 3000 3500 4000 4500 5000 5500 6000
120 4.64
208 14.4 12.4 10.8 9.61 8.65 7.85* 7.2
240 18.6 15.9 13.9 12.8 11.1 10.1* 9.28
277 25.6 21.9 19.2 17.1 15.3 14.0 12.8
480 76.8 65.7 57.5 51.1 45.7 41.8 38.4
** The above tests can also be conducted with the element removed from the tank.
Element
12.8

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Technical Training Department 9 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
GROUNDED ELEMENT TEST USING A MULTI-METER
Element
Beep
0
0.0
Check Continuity to the Tank
Note: An element’s resistance wire is
insulated so current cannot reach the
outside of the element and come in contact
with the water or the tank during normal
operation.
1. Make sure power to the water heater
is turned OFF at the circuit breaker or
disconnect.
2. Remove the wires from the element
3. Set the meter to the Ohms/Continuity
scale. Check the meter by placing the ends
of the probes against each other. If the
meter has an audible continuity check you
should hear a sound when this check is
done.
4. Place one probe on an element terminal
screw and the other on the tank. Be sure to
test both element screw terminals.
5. If the meter has an audible continuity
check and you hear the sound on either
screw terminal, the element is grounded
and must be replaced.
Note: If the meter does not have an
audible continuity check, notice the
meter reading before the probes are
placed together. Depending on the meter
the reading should be 1. Perform the
above test and if the reading changes,
the element is grounded and must be
replaced.
Tank Wall
1

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Technical Training Department 10 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
FAILED ELEMENT TEST - AMPERAGE METHOD
Amperage Check: Measures the flow of current through a wire.
Failed Element Test – using “clamp type” Amperage Meter. Many multi-meters
could be used to conduct this test but be certain that possible amperage will not exceed
the multi-meter’s limit.
Complaint: No hot water. Check for proper voltage across ECO terminals 2 & 4. If
voltage is not detected press the red reset button to activate power and re-check.
Watts divided by volts = Amps Example: 4500W / 240V = 18.75 Amps
Conditions: Power on. Thermostat is calling for heat (water in tank is cold).
TEST: CLAMP METER AROUND EACH WIRE TO THE ELEMENT(S). IF THE WATER
HEATER HAS TWO ELEMENTS, THE TOP THERMOSTAT MUST BE SATISFIED BEFORE
POWER WILL BE SENT TO THE LOWER ELEMENT.
If Amperage is not detected the element must be replaced. (See also: Grounded
Element Check with Multi-meter) If partial amperage is noted, the element may be
grounded and must be replaced.

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Technical Training Department 11 of 36 Residential Electric Svc Handbook
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GROUNDED ELEMENT CHECK – AMPERAGE METHOD
Amperage Check: Measures the flow of current through a wire.
Grounded Element Test – using “clamp type” Amperage Meter. Many multi-meters
could be used to conduct this test but be certain that possible amperage will not exceed
the multi-meter’s limit.
Complaint: A grounded element is suspected whenever the water temperature becomes
excessively hot and/or the end user must push the high limit reset to reactivate the
heater.
Watts divided by volts = Amps
Conditions: Power on. Thermostat is satisfied
TEST: CLAMP METER AROUND EACH WIRE TO THE ELEMENT(S).
IF AMPERAGE IS NOTED THE ELEMENT IS GROUNDED AND MUST BE
REPLACED. (See also: Grounded Element Check with Multi-meter)

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Technical Training Department 12 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
FIELD WIRING
L1 to Ground = 120 Volts
L2 to Ground = 0 Volts
L1 or L2 to Ground = 120 Volts
L1 to L2 = 240 Volts
L1 to L2 = 480 Volts
L2 to L3 = 480 Volts
L1 to L3 = 480 Volts
L1, L2, or L3 to Ground
= 277 Volts
L1 to L2 = 277 Volts
L1 to Ground = 277 Volts
L2 to Ground = 0 Volts

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Technical Training Department 13 of 36 Residential Electric Svc Handbook
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SURFACE MOUNTED THERMOSTAT (S) AND HIGH LIMIT (S)
The thermostats and high limits are held against the side of the tank. As the tank surface heats
or cools, a metal disc inside of the control expands or contracts to open or close electrical
contacts in the controls. They will satisfy within 10°F of setting. The tank surface has to cool
8 - 15°F to reactivate these controls.
Thermostat models WH9-6 and WH10-7 include a “high limit” or energy cut off (ECO) switch as
an integral part of the thermostat. The ECO is attached at the top of the thermostat and has a
red reset button in the middle. The ECO will shut off power to the elements if the top of the
water heater tank reaches 180° F. temperature. The ECO must be manually reset when the
tank cools by pressing the red “reset “button.
Note: If the thermostat is not flat against the tank or the insulation has been removed
from the access area, the thermostat may not read the tank temperature properly and
may cause the ECO (high limit/reset button) to trip or the T & P valve to open as a result
of high water temperature in the tank.
TEMPERATURE ADJUSTMENT
All thermostats on residential electric water heaters are set by the factory at a temperature that
approximates 120°F (HOT) and are adjustable. Other temperature indicators are “A” = 130°F.,
“B” = 140°F., “C” = 150°F and VERY HOT 160°. Read all warnings before proceeding with a
temperature adjustment. On dual element models the upper and lower thermostats are
adjustable. It is normally not necessary to adjust the upper thermostat. If the upper thermostat
is adjusted, it should not be set higher than the lower thermostat. Some models have an
external temperature adjustment knob on the lower thermostat and the temperature indicators
are the same as the above.
WH9-2
WH9-6
WH10-7

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Technical Training Department 14 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
C-2 CIRCUIT WIRING AND SEQUENCE OF OPERATION
C-2 Circuit – Standard on most single element water
heaters. Operation from a cold tank of water
•Single Element
•Single Thermostat
•Single High Limit
WH9-6 Thermostat
WIRING DIAGRAM
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.

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Technical Training Department 15 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
C2 CIRCUIT TESTING
SINGLE ELEMENT, SINGLE THERMOSTAT CIRCUIT
COMPLAINT: POSSIBLE CAUSE REMEDY
Power off Check fuse or circuit
breaker.
High Limit (ECO) Press red (reset) button (p.10)
NO HOT WATER
Element Burned Out Continuity Check (p. 8) or
amperage check (
Thermostat set above desired
temperature
Adjust thermostat (p.12) Hot
setting is about 120°F.
Element grounded Check for grounded element
See diagram (p.9 & 10)
WATER TOO HOT
Thermostat stuck in call for
heat. Replace thermostat.
WATER NOT HOT ENOUGH Thermostat set at too low a
temperature
See temperature adjustment
(p, 12)
Missing or broken dip tube Check dip tube and replace if
necessary
REDUCED HOT WATER
DELIVERY Sediment accumulation in the
tank.
Clean the tank. Drain the tank
or use a chemical de-liming
agent.

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Technical Training Department 16 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
A – 6 CIRCUIT (INTERLOCK OR NON-SIMULTANEOUS)
COMPONENTS WIRING DIAGRAM
A-6 Circuit
•2 Elements
•2 Thermostats
•1 High Limit
A-6 Circuit - Standard on dual
element water heaters non-
simultaneous / interlocked operation.
UPPER THERMOSTAT
WH10-7
LOWER THERMOSTAT
WH9-2
A-6 WIRING CIRCUIT

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Technical Training Department 17 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
SEQUENCE OF OPERATION:A-6 CIRCUIT COLD TANK STARTUP
Note: The operation
sequence at right only
applies to the initial
cold tank start. On
successive cycles cold
water entering the tank
is forced to the bottom
by the dip tube. The
lower element is
usually energized first
on successive hot
water draws as cold
water enters the tank.
In most water heater
applications the lower
element and the lower
thermostat do over
90% of the water
heating job.
The upper element is
only energized again
when the entire tank is
cold and the upper
thermostat calls for
heat.
If the upper element
burns out, the upper
thermostat call for heat
will never be satisfied
and power will not be
transferred to the
bottom thermostat and
element.

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Technical Training Department 18 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
A-9 OFF PEAK/TIME CLOCK CIRCUIT
•2 Elements
•2 Thermostats
•2 High Limits
•3 Wire
Three wire circuit for non-simultaneous element operation and single-phase power.
This circuit permits off-peak meter usage or connection to a 3-phase supply circuit.
UPPER THERMOSTAT
WH10-7
LOWER THERMOSTAT
WH9-6

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Technical Training Department 19 of 36 Residential Electric Svc Handbook
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Cold tank of water
•Single Electrical Service
•Single Phase
SEQUENCE OF OPERATION: OFF-PEAK/TIME CLOCK CIRCUIT COLD TANK START