Water Heater Diagram

Here you will find the detailed water heater diagram for electronic, gas, and solar water heaters which are either with a storage tank or tankless as reference for plumbing piping, wiring connection purposes.

If you are about to do any installation or maintenance on your water heater, you MUST follow the user manual with warning and caution. This is not an installation or maintenance guide.

Electric Water Heater Diagram

Electric Tankless Water Heater

We take the EcoSmart electric tankless water heater as sample for this type of water heater.

Wiring Diagram

The number of circuit breakers are equal to the number of heating elements inside the water heater.

Electric Tankless Water Heater Diagram - Wiring diagram


Electric Tankless Water Heater Diagram - Parts diagram
  1. Hot Water Outlet
  2. Cold Water Inlet
  3. Celsius/Fahrenheit Conversion (Press & Hold 3 sec.)
  4. Temperature Set Point Display
  5. Adjustment Knob & Temperature Control
  1. Wire Connection
  2. Brass Compression Nut
  3. Brass Compression Ferrule
  4. Electrical Strain Relief
  5. Mounting Bracket (1”)

Water Flow

Electric Tankless Water Heater Diagram - Water flow diagram
  1. Water enters the system through the inlet pipe
  2. The flow sensor detects the gallon-per-minutes flow rate and sends the information to the control board.
  3. The inlet thermostat reads the temperature of the incoming water.
  4. The control board calculates the incoming temperature and flow rate to determine the appropriate power output to reach the set temperature point.
  5. Triacs send the necessary voltage to the heating elements to achieve the correct power output.
  6. The heating elements activate and heat the outgoing water to the appropriate temperature.

Electric Water Heater With Storage Tank

We take the Bosch Electric Mini-Tank Water Heater Tronic 3000 as the sample to demonstrate the electric tank water heater diagram.

Installation Diagram

Electric Water Heater With Storage Tank Diagram - Installation Diagram
  1. Temperature & pressure relief valve, ¾ NPT male
  2. Cold water inlet ¾ NPT male
  3. Thermostat
  4. Temperature & pressure relief valve discharge line to drain
  1. ¾ NPT female tapping for relief valve
  2. Hot water outlet ¾ NPT male
  3. ¾ NPT male plug
  4. ¾ NPT female tapping for tap


Electric Water Heater With Storage Tank Diagram - Electrical connection
  1. Cable housing (internal to the unit)
  2. Wiring
  3. Protection ring for wiring.
  4. Additional grounding cable AWG16 (minimum length 152mm)
  5. Junction box left cover
  6. Nº3 self tapping screw for junction box covers fixing (with lock washer or serrated head)
  1. Junction box right cover
  2. Nº1 self tapping screw for grounding (with lock washer or serrated head)
  3. Nº4 screws for junction box fixing
  4. Junction box
  5. Housing for junction box (in the plastic front cover)

Heating Element Replacement

Heating Element Replacement Diagram

Anode Rod

Anode rod diagram


Electric mini-tank water heater component diagram

Gas Water Heater Diagram

Gas Water Heater Diagram

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