To prevent damage of inner tank during transit

Corrosion protection for the inner tank

To prevent heat loss of the hot water

The protect the heating element against mechanical damage

asbestos

glass

mica

rubber

reduce the water leakage

reduce the heat loss

increase the life of water heater

limit the load current

In kilo ohms

Zero ohm or few ohms

Infinity

High resistance in mega ohms

Thermostat contacts are welded together

Thermostat does not disconnect the heater from the supply

Open in the thermostat contacts

Thermostat set too high or out of calibration