I asked this question before, but formulated it badly. I have a LEVITON COMBINATION PILOT LIGHT SWITCH similar to the Model # 5226, but older and not identical. I do not have the original packaging or

SOURCE: I have just installed 2 Leviton decora switch with

This is a single pole light switch and should be wired as any other SP switch. The only difference is that is has a pilot light. All the white neutral wires are tied together and then pushed back in the box with none connected to the switch. The grounds are tied together with a jumper wire connected to the green screw on the switch. That will leave you with 2 or more black wires. If you have just two normally you can connect them to the two screws on the switch and it does not matter which screws. However it may be that with the pilot light you need to connect the wire going to the light to the top screw and the power wire to the bottom or vice versa. Try both ways. If you have more than 2 black wires you need to connect the incoming power black wire and outgoing power black wires together and then jump to one of the screws on the switch. The black wire left over is the black wire going to the light itself. If none of this works then it is obvious the pilot light in the switch is burnt out.

Testimonial: "Thanks a million. I will recheck the wiring tomorrow. Chas"

SOURCE: Leviton Single Pole Switch with Pilot Light Model 277W Box

Depends on whether you want the pilot to glow when the circuit is live (the main light is on) or to glow when the circuit is off. (The switch can be used either way, and I have used this switch in both configurations at different places.)

The wiring diagram is on the inside of the box.

In indicates that if you want the pilot light to glow when the circuit is off, then you only need two wires (the live and the return, usually colored black and white, respectively). However, you also need a ground. The instructions say that you need the ground for safety (and probably legal code) reasons, but I suspect that, without the ground, the pilot light won't work in this configuration.

However, if you want the pilot light to glow when the circuit is on, you probably need a three wire configuration (plus the ground).

Hope this helps.

SOURCE: I have a leviton 5226 single pole switch with

It's the same as you wire any single pole switch.

SOURCE: Recently installed leviton combination switch was

Pilot light switch is usually rated 15 amp.
Check amp rating of device.
Check volt and watt rating on nameplate of water heater.
4500watt element divided by 240volts = 18.75amps
http://waterheatertimer.org/Figure-Volts-Amps-Watts-for-water-heater.html

If you have 120Volt under-counter water heater, then add a comment.

I recommend using contactor to control water heater when using a switch rated for less than 30amp.
Contactor controls water heater. Switch controls contactor.
http://waterheatertimer.org/Ordinary.html
http://waterheatertimer.org/H230A.html