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Overheating in a water heater is a sign that there is some issue in the working of one or more parts of the water heater. This is usually caused by extensive limescale accumulation, failure of the pressure relief valve, thermostat failure, or problems in the electrical connections. Some preventive measures to avoid overheating are to check the thermostat regularly, periodic flushing of the heater and cleaning the heating elements, checking the temperature and pressure relief valves, and monitoring the electrical connections.

Water heaters are essential devices that are used on a daily basis. On average, they take up almost 20% of the total energy usage in US households.

Therefore, any issue in the operation of a water heater would affect the energy bills extensively.

One major issue that could result in the water heater drawing a lot of energy is overheating of the water present in the heater.

Not only is overheating an expensive issue, but it is also a dangerous one. If it is not attended to in the earlier stages, it could ultimately lead to the explosion of the water heater.

For these reasons, it is important to understand the factors that cause a water heater to overheat and prevent these problems from developing any further.

How to Prevent Water Heater Preventing Overheating

How To Prevent Overheating Of Your Water Heater

Overheating in a water heater is caused by some error in the operation of the heating element or some other parts of the heater.

For a gas-fired heater, this means that more BTU/h than the rated value is being used.

For an electric heater, more kW is being spent on heating the water.

There are several factors that cause a heater to overheat. The most commonly observed reasons for overheating are as given below.

Sediment Accumulation

This phenomenon is usually a direct effect of calcification in the heater.

When a lot of sediments accumulate on the surface, pipes or joints in and around the heater, the heater spends a lot of energy to bring the sediment’s temperature up along with the water.

During this process, the temperature of the water shoots up resulting in the outlet water being way hotter than it is supposed to be.

Pressure relief valve failure

If the limescale build-up happens close to the pressure relief valve, it may result in the valve failing to work. As a result, a lot of pressure would build up in the heater, eventually causing the heater to explode.

Thermostat failure

Many a time, overheating is caused by a failing thermostat.

When a thermostat fails, the water heater will not be capable of recognizing and comparing the water temperature and the preset temperature.

Thermostat failure is something that can be easily detected by checking the front panel of the heater or by following the troubleshooting guide in the user manual.

Excess power

Sometimes, due to irregular variations in the electric supply, the heating element may start overworking and heat the water to extremely high temperatures.

Overheating can also occur if the electrical supply does not meet the requirements of the heater.

The following practices can be done to avoid overheating of a tank-type water heater 

Flush the water heater regularly

Timely maintenance and regular flushing of the water heater with a decalcifying agent is necessary to avoid dangerous levels of sediment deposition.

In areas with hard water, it is recommended that the maintenance be done at more regular intervals than suggested by the manufacturer.

White vinegar is the most commonly used flushing agent. Follow the instructions provided in the user manual on how to do this procedure properly.

If you are unsure of how to proceed with the process, call a plumber to get it done the first few times.

Clean the heating elements

While the maintenance tasks for the heater is being done, do not forget to wipe clean the heating elements of the water heater. For a gas heater, the heat exchanger is to be maintained clean always.

The heating elements are subject to wear and tear and it suggested that you change the heating elements once in a while. This way, you can avoid pushing your water heater to dangerous extremes.

Maintain the pressure and temperature relief valves in their best conditions

The function of the pressure relief valve is to open to a certain degree in order to let out excessive pressure build up in the heater.

A temperature relief valve does the same when the temperature of the water goes beyond the preset value.

When either or both of these valves stop working, there is no way for the heater to let out the excess heat.

Calcification along with the failure of these valves are the primary reasons that result in the explosion of the water heater.

To avoid such a dangerous event, make sure that you check these valves regularly for proper operation. Do not wait for any signs of damage on the pressure relief valves to perform the maintenance tasks on these valves.

Any leak from the pressure or temperature relief valves means that they are malfunctioning.

If simply replacing the valves does not make any difference, it means that there is an excessive scale build-up in the heater and it might be on the verge of explosion.

At this point, it is best recommended to replace the water heater unit before any further damage occurs.

Check the thermostat to ensure it has not failed

If you feel like the water from the heater is too hot, check the thermostat setting to make sure that the water temperature is not set too high. 120˚F or 140˚F is the recommended temperature setting for most heaters.

Check the thermostat to see the temperature is not set higher than these values.

The thermostat failing to work properly could also result in overheating. Water heaters have an LED light to indicate if the water temperature is over the set limit.

If it is not ON or not blinking, it usually means that the thermostat has failed. Thermostat replacements are readily available and can be easily fixed to the water heater.

Checking the voltage and connections

Any issues in the electrical connections can also cause the water heater to overheat.

For any reason, if the heating element is receiving too much power that required, it could lead to overheating of the water in the heater.

It is, for this reason, regular checking of the voltage and electrical connections is essential.

In the end…

Overheating is usually a sign of some error in the operation of a water heater. It could be due to a mere thermostat failure or due to excessive scale build-up.

Regardless of the cause, overheating could lead to severe damages to the heater itself and even to the people around it.

For these reasons, users must ensure that they do not provide an opportunity for this to happen. Regular maintenance and checking of the heater components is the key to preventing this phenomenon.

Overheating could result in expensive repairs and even severe bodily harm. Always make sure that you take all the necessary steps to prevent this from happening.

ReviewsWorthy Team

Our team consists of enthusiastic and passionate people from different fields and experience. Some are geeks and spend most of their time among gadgets while others love nature and are always on the move! We spend 10s of hours researching and writing on each topic. The articles are then quality checked by our editors. View our "About us" section for more details about process and team.

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