The black wire on the inside panel sparks - Intermatic WH40 - Water Heater Time Switch - NEMA 1 Indoor Steel Case - DPS

Test each wire.
Black to red 240Volt
Black to White 120Volt
Red to white 120Volt
The white might be ground

Copy following links:
http://waterheatertimer.org/See-inside-main-breaker-box.html
http://waterheatertimer.org/images/Inside-Main-Breaker-Box-12.jpg

Gene
h

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Copy following link for wiring tankless electric water heater:
http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater.html

2) Look at label on side of unit for total KW

3) Product manual shows 24 Kw or 24,000 watts
24,000 watts divided by 240 volts = 100 amps
So your service panel must be about 250Amp rating to support this tankless electric water heater.
http://waterheatertimer.org/pdf/Tempra_tempra-plus-Tankless-electric-water-heater-manual.pdf

4) Look inside the unit to see how many L1L2 terminals show.
You should have two sets L1L2 terminals
http://waterheatertimer.org/images/Terminals-2-tankless-200.jpg

5) You need TWO 60 amp double pole breakers to supply power to this unit.
This means you need TWO #6 wires from one breaker going to L1L2.
And you need TWO MORE #6 wires from 2nd breaker to other set of L1L2 terminals.

6) Add comment for more help Jan 2013

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Check for a bad fuse in panel first, then with a 12 volt test light or multimeter, check for power in to switch, as well as out when in on position if it's easy to get to. If not, turn switch on and test for voltage at brown wire to thermostat terminal, that comes from inside at back of water heater from switch inside. If it has cut-out switch in plastic sleeve attached, be sure to check for power on both ends of that cut-out switch. If power only in but not out, replace it. As I said,that brown wire comes from switch, so if no power to it, check at switch. The other brown wire goes back to connector on ignition board. If power is there, turn switch off, take an eraser on end of a pencil and rub contacts on ignition board/module to clean them off, as well as spray electrical cleaner on contacts of connector to make sure you have a good connection. Check all ground connections as well, and if you have 12 volts at brown wire to connector on ignition board but still no spark, replace ignition board/module.

I'm thinking when you say black box, that you also have a wall switch with a symbol like a lightning bolt and you switch that on as well as checked breaker panel to make sure breaker is on as well.
With that said, you'll have 2 of 3/8" nuts holding that black cover on. Remove top one and loosen bottom one and pull cover off. ( Be sure power is off to unit while doing this.) You'll find the element in behind it. Put a voltmeter on black to element (red probe or alligator clip) and (black probe) to ground where you see green wire connected to tank. Turn breaker on then switch at wall. You should hear a relay click and 120 Volts should show at black wire ( red probe) . If you've got 120 volts there, shut off all power, drain water heater and replace element.

Starter module ,or the electrode ,change them both.

You have water heater with two elements.
Two-element water heaters are 240Volts.

1) Lets talk about what makes a 240Volt circuit
See basic water heater circuit:
http://waterheatertimer.org/B220C.html

Open link, and illustration at top of page is your water heater circuit

Notice that two insulated wires come from the circuit breaker and go to the water heater.
These two wires are 120volt each. When these two 120Volt wires combine, they create 240Volts
These are called hot wires because they come from the hot busbars.
There is also a bare copper wire that comes from neutral busbar.
The bare copper wire is a safeguard, and is not necessary for the 240V circuit to work.

Inside each circuit breaker box is 1 neutral busbar, and 2 hot busbars.
Open image below, and it shows typical residential breaker box
http://waterheatertimer.org/images/Inside-Main-Breaker-Box-420.jpg

In a residential home, each circuit takes two wires to complete the circuit.
For 120Volt circuit, you need 1 neutral wire and 1 hot wire to complete the circuit. These are usually a black and white wire. The bare copper wire is a safeguard.
For 240Volt circuit, you need 2 hot wires to complete the circuit, and each hot wire comes off a different busbar. These can be a black and white wire, and sometimes a black and red wire. The bare copper wire is a safeguard.

With a 240Volt water heater the two hot wires connect to the black and red wires located on top of water heater.

2) Let's talk about wiring inside a water heater.
http://waterheatertimer.org/images/WH-w-combined-530.jpg

Open image on link above, and it shows your 240volt water heater wiring.
The 2 hot wires from breaker box connect to the red and black wires on top of heater.
Inside each water heater, the wires are color-coded and will appear the same, or nearly the same, as shown on link above.
As long as your wiring appears like the image, and the hot wires from breaker box connect correctly, and the circuit breaker is working fine, then your water heater will work.

Add a comment any time.

3) More electric water heater links about water heaters, thermostats and tank wiring:
http://waterheatertimer.org/How-electric-water-heater-works.html
http://waterheatertimer.org/How-water-heater-thermostat-works.html
http://waterheatertimer.org/How-to-wire-water-heater-thermostats.html

Normally the red light stays on for hydro operation, so within 1/2 hr or so you should have hot water. Red light on gas means problem lighting. A few things to check. Make sure switch at back of water heater is on as well as breaker in panel, for hydro operation.
As far as gas side goes, try going outside and drop cover down, and pull the connectors of and on a couple of times at the spark module, just to make sure you have clean contact, and have someone try switch after, and let me know if it's at least trying to spark. If still not working, there should be a thermal cut-off switch in the brown wire running to center area of water heater to the thermostat, and ECO. ( where square piece of black foam covers them) That thermal cut-off has a clear plastic sleeve over it. Take that out of the circuit. Simply pull it apart at both ends, and then connect wire from spark module directly to THERM/ECO, where it was before.( your just eliminating that piece, and going direct.) See if it lights now, and let me know. Do you have a 12 volt test light, or multimeter? Also, with it turned off, take your finger and push in between spade connectors on the THERM, and ECO, and make sure there isn't a little reset in center that has tripped.

According to the user manual below, it's a 50 amp heater, therefore, you need 6 AWG electrical cable and a 50 amp double pole (220 volt) breaker in the main service panel.

You need two hot wires and a ground wire. The cable would be specified as 6/2 w/ ground. The 2 hot wires in the cable would be red & black or black & black -- these attach to L1 & L2 respectively. ( L = Line )

More info, let me know.

Charlie

http://ecx.images-amazon.com/images/I/A1b%2BxE2vITS.pdf

some times the wire for the ignitor will get burned inside the chamber, if this happens you will not get a spark and will need a tech, but turn the gas valve to the piliot position hold down the button on the gas valve while clicking the electric ignitor button, look thru the site glass towards the left side of the burner assembly while doing this, if there is no spark it will have to be taken apart and replace the spark ignitor, not a big job you just have to make sure the seal on the burner cover doesn't tear or get damaged

could be thermocupple