No heating and cold water are two unpleasant situations that occur when the boiler does not properly work. There can be several causes and it is important to know what to do and how to intervene to solve the problem. Let's find out together.



What should you do when the boiler goes into lockout?


The boiler is a fundamental heating system, at any time of the year. In fact, thanks to it it is possible to operate the radiators and produce domestic hot water.

When it goes into lockout it means that an internal element prevents it from working properly. The boiler stops for safety reasons and prevents even more complicated and serious problems from arising.

If provided by the model, an alphanumeric code will appear on the display indicating the type of fault. You can consult the boiler manual to understand what happened: if it is impossible to intervene on your own, you need to call a specialised technician to avoid further nasty surprises.



Boiler lockout: the main causes


Among the most common causes that determine the boiler lockout we may find:

  • the formation of limestone;
  • damage to the electrical system;
  • gas interruption;
  • excessive air in the radiators;
  • low water pressure.

Let's see in detail how the different hypotheses affect the operation of the boiler.

  1. Limescale is one of the toughest enemies of plumbing systems and your boiler can pay the price for it. In fact, the incrustations do not allow a regular flow of the hot water which does not reach sufficient pressure.
  2. The water pressure, on the other hand, should never be too high or too low. Each boiler is equipped with a pressure gauge, which indicates the level: to be optimal, it must be between a minimum of 1.2 bar and a maximum of 1.5 bar.
  3. In some cases the boiler lockout is caused by excessive air in the radiators. The presence of bubbles does not allow homogeneous water heating and the device consequently stops.
  4. Other reasons for malfunctioning are related to damage to the electrical system, due to a lack of electricity or to an insufficient draught of the exhaust gases.

Maintenance is fundamental: the boiler must be regularly checked. If you are a landlord, an annual boiler service is a legal requirement. A qualified Gas Safe registered engineer must, by law, check gas appliances and flows annually and the check includes boilers.

Relying on the knowledge and skills of a specialised technician is always the best solution.

How to reset a gas boiler


Gas boilers are the most common. Technological development and innovations have also made it possible to introduce condensing boilers which, unlike traditional ones, allow energy to be recovered from exhaust fumes. This reduces the emissions of harmful substances into the atmosphere and optimises costs.

In case of boiler lockout, we often rely on the reset process: the button is pressed for a few seconds and then released. In this way the boiler memory is erased and it is restored to the initial status. It is a valid hypothesis, but it may not be enough.




The causes of a lockout are different and it is therefore necessary to carry out detailed diagnostic operations with the boiler off and done by competent technicians.

  • If the problem is related to limescale, it can be remedied with the help of a plumber to clean the exchanger and possibly install an anti-limescale filter in the boiler.
  • If, on the other hand, it depends on the water pressure, it is possible to intervene by acting directly on the pressure gauge and bringing the boiler back to the indicated values.
  • The pressure gauge is also useful if there is too much air in the radiators. If by checking it, you notice that the pressure indicated is excessive, you can then open the valve of a radiator to vent it.

The boiler can also go into lockout due to the interruption of gas distribution. Without gas, the pilot flame, which is indispensable for the functioning of the heat generator, does not ignite.

However, the blockage could directly depend on the obstruction of the gas valve that feeds the boiler: another hypothesis that requires the help of a specialised technician.

Why does the boiler stop working?


It may happen that, after having started regularly, the boiler stops working. The unexpected depends on the activation of the security system which detects some serious problems.

  • The burner is dirty and a red light turns on.
    If the problem recurs even after a reset attempt, contact a specialised technician to clean or replace it.
  • The lack of air exchange and poor ventilation favour the accumulation of dangerous and harmful substances.
    The boiler then goes into safety mode, stopping working. It is necessary to contact a qualified person.

Locking can finally derive from a problem linked to the thermostat and, in particular, to the discharge of the power batteries.

A mishap that can be avoided with the installation of a smart thermostat. Thanks to its advanced technology, it warns the user in time to change the batteries, by sending a notification on the smartphone with which the smart thermostat can be easily managed.

Replacing the batteries is easy and immediate: just follow the instructions in the booklet and the boiler will work correctly again.

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