.Working Principle

Water heaters operate on the basic principles of thermodynamics, primarily:

• Conduction (heat transfer through solid surfaces),

• Convection (movement of hot water upward and cold water downward),

• Thermostatic control (to regulate temperature).

Key Components and Their Functions

1. Tank (in storage models)

• Material: Usually steel with an internal glass lining to prevent rust.

• Function: Stores hot water and maintains it at a preset temperature.

• Insulated to reduce standby heat loss (via foam or fiberglass).

2. Heating Element (Electric) / Burner (Gas)

• Electric Heater: Contains one or two immersion heating elements similar to those in an electric kettle.

• Gas Heater: Uses a burner assembly beneath the tank. Combustion heats the bottom of the tank.

• Some advanced systems use modulating elements for efficient energy use.

3. Thermostat

• Detects water temperature and turns the heating element or burner on or off.

• Typically set between 110°F to 140°F (43°C to 60°C).

• In electric models, each heating element may have its own thermostat.

4. Dip Tube

• A long tube that directs cold water to the bottom of the tank.

• Promotes stratification: cold water at the bottom, hot water at the top.

5. Hot Water Outlet

• Located at the top of the tank, where hot water naturally rises.

• Delivers hot water to the home’s plumbing system.

6. Anode Rod

• Sacrificial metal rod (usually magnesium or aluminum).

• Attracts corrosive elements in water to prevent tank rust.

• Crucial for prolonging tank life (should be checked every 2–3 years).

7. Temperature & Pressure Relief Valve (T&P Valve)

• Safety mechanism.

• Releases water if the temperature exceeds ~210°F or pressure goes above 150 psi.

• Prevents tank explosions due to overpressure.

8. Flue Baffle / Exhaust Vent (Gas Models)

• In gas models, exhaust gases from combustion rise through a central flue.

• A baffle in the flue increases contact time for heat exchange before venting out.

• Flue gases exit via chimney or side vent.

9. Drain Valve

• Located at the bottom.

• Used to flush out sediment or to drain the tank for maintenance.

Step-by-Step Operation

 For Electric Water Heaters:

1. Cold water enters the tank through the dip tube.

2. Thermostat detects the water is below the set temperature.

3. One or both heating elements activate.

4. As water heats, convection currents form (hot water rises).

5. When temperature is reached, the thermostat cuts off power.

6. When a hot water tap is opened, hot water exits through the outlet.

7. Cold water refills the tank, and the cycle continues.

 For Gas Water Heaters:

1. Cold water enters via dip tube.

2. Thermostat senses water is cold, triggering gas valve to open.

3. Gas burner ignites via a pilot light or electronic igniter.

4. Flame heats the bottom of the tank; hot gases rise through the central flue.

5. Heat is transferred to the surrounding water through conduction.

6. Heated water rises and is stored at the top until needed.

7. Exhaust gases exit via the flue system.