The Reliance Water Heater Company produces the 606 Series of electric water heaters with capacities ranging from 27 to 119 gallons in a variety of shape and size configurations. The heaters have two standard 4,500-watt heating elements, one at the bottom of the tank and one placed higher, with a thermostat attached to each element. Both elements can fail due to power surges or mineral deposit buildup, although failure is more common with the lower element because it's in use more. Follow these instructions to replace either element.
Turn off the electrical supply to the water heater from your circuit breaker or fuse box. Turn off the water supply at the inlet valve.
Attach a water hose to the drain valve at the base of the heater and route it outside or to a floor drain, then open the drain valve. Open a nearby hot water faucet to let air into the tank as the hot water drains. Leave it open.
Remove the screws attaching the access panel door to the tank. Pull off the door and remove the insulation behind it, which covers the thermostat.
Unclip the terminal cover from the top of the thermostat and set it aside. Disconnect the two wires from the heating element, located directly beneath the thermostat.
Use a wrench to turn the element counterclockwise and unscrew it from the water heater. Remove it, making sure the old gasket comes out also.
Slide the element gasket onto the threads of the new element. Screw the element into the tank and tighten it securely with the wrench.
Close the drain valve and remove the hose. Turn on the water supply and allow the tank to fill until only water---no air---is coming from the nearby hot water faucet. Close the faucet.
Connect the two wires to the new element. Clip the terminal cover onto the thermostat and replace the insulation. Reattach the access panel door, and then turn the power back on.