LEFT SIDE: A water heater pop-off safety valve.

CENTER: This large piece of calcium is from the heat exchange (flue or chimney) which runs through the center of the gas water heater. This large piece of calcium is 10-1/2" long, 4" wide, 3/4" to 2-1/2" thick and weighs more than 3-1/2 pounds.

RIGHT SIDE: This is a heating element from an electric water heater.

Liming
Inside View
Heater Cut Away
Inside Water Heater Views
Calcium Views
Scale Buildup Views