How to remove and change the heating element from the boiler – necessary tools and instructions

The storage electric boiler is currently the most popular type of water heater. It is easy to operate and connect, making it a crucial component in supplying hot water.

When choosing a water heater, the primary consideration for consumers is the volume of the storage tank. Occasionally, the device is selected based on its model and internal design. However, the technical passport does not always provide information about necessary maintenance, which can result in malfunctions and the need to replace parts of the boiler.

The electric tenon is an essential component in the operation of the equipment. It may unexpectedly fail, requiring prompt repairs, especially if the water heater is the sole source of hot water.

If you want to replace the tenon in the boiler on an "Ariston" model, this step-by-step guide will walk you through all the necessary work to remove and replace the electric heater on your own.

Internal design of the water heater and the principle of operation of the heating element

An electric storage water heater is a tank made of steel or stainless steel alloy that can store and maintain a specific water temperature until it is fully or partially used. The boiler includes a heating element, typically made of copper alloys, with an average capacity of 1.5 – 2.0 kW.

The heating element can be designed in two types:

• Dry tenon – a heating element enclosed in a protective housing that does not come into contact with water.
• Immersion heating element – a heating element without a protective layer, often referred to as a "wet heating element".

Both types of heating elements do not provide any specific advantages as long as the magnesium anode fulfills its protective function.

The magnesium anode serves as a safeguarding rod that comes with every water heater. By being more reactive and interacting with water first, it prevents the oxidation process of the heating element and the inner walls of the boiler tank. All the electrochemical processes happening within the heater are manifested on this component and gradually deteriorate it.

Once the protective rod is exhausted, other components will come into contact with the water, resulting in the wet heating element being the first to suffer corrosion, as its copper alloy is more active compared to steel or stainless steel. In the event of such a failure, only the replacement of the heating element will be necessary. However, in a water heater with a safeguarded core, electrochemical reactions solely impact the equipment’s walls, leading to the tank’s deterioration. Consequently, the water heater starts to leak and becomes unusable and irreparable.

A regular boiler maintenance includes the periodic replacement of the magnesium anode. This task needs to be done every 6 to 9 months, depending on the water’s composition.

However, what should be done if the anode was not replaced on schedule and the heating element is now damaged?

Step-by-step instructions for replacing the electric heating element

When replacing the therunner in the boiler, it is crucial to approach the entire process with care and caution. To prevent any damage to other components, it is highly recommended to thoroughly review the complete instructions before beginning to service the equipment.

There are several reasons to repair a water heater:

• The water does not heat up.
• It takes a long time for the water to heat up.
• The water heater frequently turns on and off.
• The water appears cloudy and has an unpleasant odor.

Depending on the model, there are three different methods for mounting the boiler element: a large 55 nut, a pressure plate, and a flange with circular mountings.

Replacing the heating element in a boiler with a 55 nut.

When starting the repair process, it is essential to first turn off the power supply to the equipment. To disconnect the pipes or flexible hoses connected to the boiler, use a stopcock to shut off the cold water supply and proceed with caution. To expedite the process of draining the water, prepare a container and a hose in advance and use a wrench to unscrew the water supply connection along with the boiler safety valve. Make sure to direct the hose towards the sewer and secure it onto the threaded part, while ensuring that a container is positioned beneath the water heater.

The 55 water heater is equipped with a nut.

Once all the water has been drained from the boiler, the next step involves removing the protective housing. By using a Phillips screwdriver to loosen two bolts, the bottom cover of the water heater can be taken off. The protective casing reveals the electrical connection to the heating element and thermostat. Additionally, the fixing nut that secures the outer part of the water heater structure is located in this area.

Prior to disconnecting the electrical wires from the automation, it is important to ensure that their correct connections are properly fixed. One option is to take a picture or make a note on paper, especially since the wires are typically different colors.

All nuts should be unscrewed counterclockwise. If necessary, the boiler can be detached from the wall and turned upside down to continue with the disassembly process.

Hub wrench 55

To unscrew the nut, you can either use a No. 2 gas wrench or a hub wrench with a size 55. If you’ve been using the water heater for a while, there’s a chance that a significant amount of scale has built up on the heating element, making it difficult to remove. To solve this issue, you’ll need to gently tap and remove the scale using a blunt object that won’t cause any damage.

Get a full heating element complete with a magnesium anode and thermostat.

Prior to installing a new heating element, it is essential to check the condition of the magnesium anode. In most instances, the protective element is completely deteriorated, with only a threaded rod remaining. The magnesium anode is sold separately and plays a crucial role in the heating element’s performance and lifespan. Prior to purchasing the protective element, make sure to confirm the exact diameter of the threaded connection and the thread pitch by screwing the rod into its designated spot.

Tools needed for this task: gas wrench #2, wrench for the hub, and a screwdriver.

Replacing the heating element in a boiler with a retaining bar

In newer boilers, the internal structure will have some variations compared to older models, as they are equipped with a clamping bar instead of a fastening nut.

All the necessary steps should be followed in the usual order until the main nut is loosened. Similarly, make sure to de-energize and stop the flow of water, remove the protective cover, and securely connect or disconnect the electrical wires.

When it comes to disassembling this particular type of boiler, one crucial guideline is to avoid turning it upside down. This is because the electric tenon is securely attached to the main nut, and if unscrewed incorrectly, it could fall inside and potentially damage the inner wall of the water heater. As a result, all maintenance and replacement tasks must be performed exclusively with the heater in its standard position.

Boiler model with a single nut and securing bar

The thermostat can be detached in the same manner as in all Ariston water heaters. Disconnect the thermometer from the entire structure with a quick motion.

The primary nut is secured to the securing bar; by loosening it, you can extract the flange with the heating element. Before removing the flange, it should be gently rocked and twisted.

A collection of ratchet wrenches

Take note of the state of the magnesium anode and, if needed, replace it.

Required tools: ratchet wrench, socket wrench, and a Phillips screwdriver.

Replacement of the heating element in a boiler with a flange and fasteners in a circle

In the newer and more popular versions of water heaters "Ariston", a flange with mounting bolts ranging from 4 to 6 is already installed.

All standard procedures should be carried out in the same order as with previous models of water heaters. De-energize the device and drain the water, remove the protective cover and secure the wire connections. You will need to unscrew the safety valve in a mandatory manner, as it will obstruct the unscrewing of the bolts.

In this particular type of water heater, the thermostat is positioned on the flange, which is attached with bolts in a circular manner. In even newer iterations of the equipment, nuts are screwed onto the built-in studs.

Disengaging the thermostat from the water heater

The method of disengaging the thermostat from the main structure remains unchanged – an abrupt motion to remove it from the clamps, after having previously disconnected the wires.

A socket wrench or ratchet wrench of the appropriate size can effectively loosen the bolts or nuts.

Once the fasteners have been loosened, the flange securing the heating element can be detached from the boiler tank. Always be mindful of the magnesium anode. If wear is significant, it is advisable to replace it as well, in order to avoid carrying out similar procedures in the near future for the purpose of replacing the protective element.

Replacement of the thermostat in a flat water heater and replacement of the dry thermostat

A horizontal water heater can be equipped with two heating elements, and in order to determine which one is faulty, it is necessary to remove both heating elements. Follow the prescribed procedure to replace the damaged heating element. The process of unscrewing the fasteners is no different from regular water heaters with a single terminal.

Ariston water heater model equipped with two heating elements.

This particular model of boiler is distinct from standard ones due to its dry heating element and the presence of a protective bulb inside the tank. However, the location and fastening details of the nuts do not differ.

The necessary tools for servicing this water heater include a socket wrench, a ratchet wrench, and a screwdriver.

In order to prolong the lifespan of the equipment, it is important to follow a few rules:

• Service the water heater biannually.
• Avoid heating water above 70 degrees.
• Install a filtration system.

It is crucial to ensure that all gaskets are intact when reassembling the boiler. Also, pay close attention to the tightening torque of nuts and bolts to prevent thread breakage.