Cold and no hot water are the two major inconveniences that occur when the boiler does not turn on. A particularly annoying and irritating eventuality during the winter season, when the heat generator is needed to achieve thermal comfort in the coldest period of the year.


What to do if the boiler does not turn on?


The causes that prevent the boiler from starting regularly can be different. Knowing them allows you to understand how to intervene, bearing in mind that the best way to solve the problem is to rely on the knowledge of a specialised technician.

To identify the reason why the boiler does not turn on, you can read what is indicated on the display, if the model supports it. The system errors reported by the panel make it possible, for example, to understand if a safety block, which prevents the heat generator from working, has occurred. A reset, using the appropriate button, is not always a valid solution.

The problem could in fact be found elsewhere.


  • Water pressure. Too low water pressure, with a level below the optimum range of 1 to 1.5 bar, is not sufficient for boiler operation. The pressure gauge indicates the level and low pressure can be linked to a water leak rather than air bubbles in the system.
  • At the same time, boiler lockout can be caused by too high pressure. It will therefore be necessary to adjust the water level to the indicated values.




  • Limestone. Limescale is an enemy of plumbing systems and the boiler is no exception. Encrustations due to the presence of hard water are among the possibilities that prevent the boiler from turning on. It will therefore be necessary to carry out a detailed cleaning of the components, also installing an anti-limescale filter to prevent the unexpected from happening again in the future.
  • Boiler burner. It is the key element in gas boilers because it triggers the spark to burn the gas and, consequently, to produce domestic hot water. When it is activated regularly, the flame of the boiler lights up. If, on the other hand, the pilot flame does not start, then it is necessary to check the state of the burner. Over time, dust and debris build up and it may have clogged nozzles or an ignition system failure.

Considering the complexity of the causes that determine the failure, calling a specialised technician is essential. On the other hand, the user can always check if the boiler is correctly connected to the current rather than if gas and water taps are open.

How to understand if the boiler board has burned out?


The technological development of boilers, now capable of guaranteeing ever higher performance, is also made possible by sophisticated and functional electronic components. The risk, however, is that a problem with the electrical equipment compromises the regular functioning of the heat generator.

A key role is played by the boiler board. It manages the main functions and monitors the boiler safety system. When it does not work properly, the boiler will not turn on.

The board is susceptible to power surges and instability of the supply current, causing damage or burnout. These unforeseen events can also be caused by weather events or interventions on the energy supply system or, simply, by wear.

Surges and instabilities affect fuses and other components. False contacts are also generated and they may totally or partially compromise the integrity of the board. The boiler shuts down and gives no sign of life.

It thus becomes necessary to remedy, always relying on the knowledge of a professional technician.

How do you reset the boiler?


A first attempt to restart the boiler is a reset which clears the memory of the heat generator. To proceed, in most models, the round light indicating boiler shutdown must be pressed for at least 5 seconds before releasing the button.

The reset allows you to resolve some anomalies, but has no effect if the cause of the shutdown is linked to more complex situations.

When lucky, the temporary lockout is resolved with the reset. However, if it is evident that this operation is not enough to restart the boiler, it is essential to contact an assistance service.



Why is the boiler off?


There are many reasons that can stop the boiler from turning on: from electrical faults to pressure problems, from wear to the formation of limescale, from anomalies in the exhaust fumes to interruptions in gas and light supplies.

The bad surprise, among other things, often catches the user unprepared when he returns home after a day out for work or pleasure. However, there are some tools to check the status of the boiler even remotely.

Thanks to brand new devices connected to the wifi network, the boiler can be switched on and off from the applications installed on your smartphone. Not only: the smart boiler modules warn through notifications in the event of anomalies in the heating system, allowing you to always keep the situation under control.

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