Step 1: Power Isolation and Water Shut-Off

1. Switch off the mains electrical supply to the water heater at the circuit breaker
2. Remove the fuse if applicable to ensure complete isolation
3. Close the service valve or cold water supply valve to stop water entering the unit
4. Open a hot water tap to relieve pressure in the system

Step 2: Drain the Water Heater

Draining requirements vary by model:

1. Andris R series (under-sink models): Disconnect pipes and remove the heater from the wall
2. Andris R series (over-sink models): Undo the cold water supply pipe and open a hot water tap to drain
3. THER series: The appliance must be drained to enable replacement of the armored heating element
4. Steatite and Professional TECH series: No need to drain the appliance for heating element replacement—these models allow element access without draining

For units requiring drainage:

1. Place a bucket underneath the drain valve or lowest connection point
2. Open the drain valve or disconnect the cold water inlet to allow water to flow out

Caution: Removing flange screws on certain models will release stored water

Step 3: Access the Heating Element and Components

1. Unscrew the screws securing the front cover (typically 2 screws on most models)
2. Remove the cover carefully to expose the electrical components, thermostat, and water container
3. Locate the heating element—usually mounted at the bottom or side of the tank

For Andris R models:

• The heating element may be removed after taking out the thermostat phials (on 30L models) by undoing the M6 nut
• The assembly should then be turned through 90° anti-clockwise to ease removal from the water container

Step 4: Disconnect Electrical Connections

1. Note wire positions or take a photograph to ensure correct reconnection
2. Disconnect wires from the heating element terminals
3. Remove the thermostat phials carefully if present—these are temperature-sensing probes that extend into the tank

Step 5: Remove the Old Heating Element

1. Undo the mounting nut or bolts securing the heating element
2. Remove the heating element from the tank
3. Inspect the sacrificial anode (if accessible) for corrosion or depletion. The anode should be checked annually and replaced as necessary
4. Clean the element flange area of any scale or debris

Important Note: If the heating element is heavily coated with scale, descaling and removal of lime deposits should be performed at the time of inspection.

Step 6: Install the New Heating Element

1. Apply PTFE tape to threaded connections if required
2. Insert the new heating element into the tank opening
3. Secure the element by tightening the mounting nut or bolts to the specified torque
4. Reinsert thermostat phials into their original positions (for models with external thermostats)
5. Reconnect wires to the heating element terminals following the original configuration

Step 7: Reassemble and Refill

1. Reattach the front cover, ensuring the regulation knob is properly coupled with the thermostat
2. Open the cold water supply to refill the tank
3. Open a hot water tap to allow air to escape from the system
4. Wait until water flows steadily from the tap, indicating the tank is full
5. Check for leaks around all connections

Step 8: Restore Power and Test

1. Restore power by switching the circuit breaker on and replacing the fuse
2. Set the thermostat to the desired temperature (recommended maximum 60°C in hard water areas)
3. Allow 30 minutes for the temperature to stabilize between settings
4. Check that the neon light (if present) illuminates, indicating the heating element is working under thermostat control
5. Verify hot water is reaching the taps at the expected temperature

Step 9: Final Checks

1. Inspect for leaks after the unit has reached operating temperature
2. Check the thermal cut-out has not operated—if it has, the cause must be found before resetting
3. Test pressure relief valves where fitted by lifting the test lever or turning the test knob
4. Confirm proper disposal of the old unit, adhering to environmental regulations