Electric Hot Water Heaters are generally fairly reliable and normally provide trouble free operation.

The most common fault or problem with them is a blown element and to a lesser degree a faulty thermostat.

One of the causes of a blown electric hot water heater element is poor water quality, water which comes from a bore or water which is high in iron content can react with the metals of the element which leads to corrosion. Once the outside of the element coil has corroded through, it is the end of your element.

Changing an element is a straight forward operation – there is nothing difficult about it at all -well within the scope of the DIY guy. There are couple of safety precautions which you need to take first to ensure that you do not get electrocuted. Water and electricity are not a good combination at all.

First, before commencing any electrical work on a electric hot water heater, turn the power off to it at the switch inside the hot water cupboard or near your hot water cylinder, secondly isolate the power to the hot water cylinder at the switchboard of your house by either removing the fuse and/or circuit breaker. Failure to do this and commencing work can result in serious injury or death.

So you have isolated the power to the hot water cylinder, now you need to empty the hot water cylinder of water, it is surprising how many people try and change an element without emptying the cylinder first!

Most hot water cylinders have a drain pipe underneath them which drains to the exterior of your house, it will usually have a cap on it and sometimes an isolation valve. Isolate the water going into the hot water cylinder and then drain your cylinder. When you have drained it, this is always a good opportunity to give it a flush out, you will be surprised at the amount of sludge which sits at the bottom of a hot water cylinder.

Firstly remove the element cover which protects the element and thermostat.
Remove the wiring from the element, including the earth. If you are not sure where the wires go, simply draw a diagram so you know where they go after you fit the new element.

Use an element spanner, remove the element. Fit the new element making sure you remember to fit the new washer supplied! Tighten it up. Then reconnect the wires, referring to the diagram you drew earlier. Put the cover back on. Close the cylinder drain if you haven’t already done so, and screw the drain cap back on if fitted.

Turn on the water supply to the hot water cylinder, open some hot water taps around the house to let the air out of the cylinder as it is filling. While the cylinder is filling, it is a good idea to check the temperature setting on your electric hot water heater thermostat – this needs to be set at around 65 degrees Celsius to prevent the growth of bacteria. Once you have water coming out of the hot taps, you will know the cylinder is full. Close taps, recheck around the element for any water leaks.

Turn power supply back on to your hot water cylinder, and if you have done everything correctly, within an hour or so, depending on the size of your water heater, you should have hot water.

If you have any doubts about tackling this task, or get into difficulties, please contact your local electrical contractor.

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Filed under: Hot Water • Tips

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