The replacement of an immersion heater may be a task best completed by either your electrician or plumber. If there is an inexplicable lack of hot water, or if it takes a long time for your water to heat up – it’s probably time to replace your immersion heater. If your water gets too hot too quickly, it is more likely that you need to replace the thermostat in the immersion heater rather than the entire unit. Replacing an immersion heater is a reasonably simple task.
Before starting, ensure that you have turned off the electricity at the mains power. For additional safety, you should remove the fuse for the immersion heater in your double pole switch. The next task is to turn off the water supply feeding into the heater. This may be with either a valve at the heater itself; if you cannot find one, then you will need to turn off your water at the mains. Make sure to drain all of the hot water out of your heater by running the hot taps and by the drain valve on the heater.
Once all of the water is out of the tank – and double checking that the electricity is off – then you can tackle the wiring. Unhook the wires for the thermostat and move them out of the way. Next, you will need to unscrew the nuts securing the heater in place. If the unit has been in place for a period of time, you may need WD-40 to loosen the nuts and bolts. Remove the heater element you wish to replace with a new one. Insert the new heater element, ensuring that you get the same length element. Use plumber’s tape around the bolt to secure it tightly, reconnect the thermostat wiring, set the temperature, and then refill the tank.
Please note that some electrical work in the home should now only be completed by a fully qualified electrician. Check this before you perform any work yourself.