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Use ordinary tester
1. Test black wire to ground screw > and then
2. Test black wire to white wire > and then
3. Test white wire to ground screw
>> if no light shows with these 3 tests, then electricity is off
tester and green ground screw
Method 1:
Test where wire arrives at water heater
> Turn off electricity at circuit breaker box
> 120 Volt water heater will have 20Amp breaker
> 240 Volt water heater will have 30 Amp breaker
> Read information on side of tank to see appliance voltage [or read owner's manual]
> Electricity arrives at water heater in wire coming from circuit breaker box
> Wire is held to water heater with a clamp > leave clamp alone
> Look for metal plate (next to wire) > under metal plate are wiring connections
> Remove screw or screws so the metal plate comes loose
> Inside there are 3 sets of wires: > a bare copper usually attached to green ground screw > 2 white wires covered by wire nut > 2 black wires covered by a wire nut
> 240 Volt or 120 Volt there will be 3 wires
review basic circuit
> The white and black wires are covered with wire nuts
> Leave bare copper wire attached to water heater
> Remove wire nuts that cover black & white wires (while doing this,
do not touch any bare
wire, do not touch metal
water heater, do not lean against water heater, do not touch metal
pipes or metal ductwork, always wear dry clothes and dry shoes and
never stand on bare soil or
damp floor, put down dry boards or plywood)> So now, the wire nuts are off black & white wires
>
Test black wire to bare copper wire
> if light shows on tester, then electricity is present >
solve problem: try turning off another breaker>
Must double-check result
> test black wire to white wire -and- finally test white wire
to groundIf no light shows with these 3 tests, then electricity is off.
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Example of upper thermostat
Method
#2 for checking water heater: Test upper thermostat
> Read label on side of tank to see appliance voltage 120V or 240V [or read owner's manual]
> Remove cover from side of water heater to reveal thermostat see image
> Thermostat is 1-1/2" wide x 4" tall and has red reset button
> Use flashlight and look closely at markings on thermostat
> Topmost 2 screws are labeled L1 and L3 -or- they are labeled 1 and 3
> Test across L1 to L3 > test light will come on if electricity is present see diagram
See troubleshooting steps for electric water heater
How to test electricity from circuit breaker to water heater
Element
Method
#3: Test screws on upper or lower elements
240 volt tank
If water heater has 2 elements and 2 thermostats, then it is rated 240V.
240V water heater thermostats turn off 1 leg of 240V circuit.
This means upper and lower elements will test for 120V at all times.
> Take covers off water heater to reveal thermostats and elements see image
> Elements are 1-1/2" in diameter > each element has 2 screws where wires attach
> On 240V water heater, 120V electricity is always present on both screws > this is true for both upper and lower element
> Test screw to any bare metal part of water heater using ordinary tester
> If light on tester comes on, then electricity is present
How to replace circuit breaker
