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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 in dual-element 240 volt tank
> Read information on side of tank to see appliance voltage [or read owner's manual]
> Take cover off water heater to reveal upper element and thermostat see image
> Upper thermostat is about 1-1/2" wide x 4" tall and has a red reset button
> Use flashlight and look closely at markings on thermostat
> The topmost 2 screws are labeled L1 and L3
> Test L1 to L3 > test light will come on if electricity is present see diagram
> See full troubleshooting steps
Element
Method
#3 for checking water heater: Test screws on upper or lower elements 240 volt tank
> Take covers off water heater to reveal thermostats and elements see image
> Elements are 1-1/2" in diameter > each has 2 screws where wires attach
> On 240V water heater, 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