My boiler is leaking: what should I do? How to identify the problem?

When you notice a small puddle of water under the boiler, it is natural to worry. However, the majority of detected leaks will only be benign, and can be repaired on your own, without having to engage in expert work. Here are the most likely causes of a boiler leak, and the right things to do before calling a technician.

Why can a boiler leak?

All boilers can leak, whether electric, oil, gas or wood. The causes can be varied but not multiple. They will boil down to the following eventualities:

  • A pressure problem : This is the reason most often noted by repairers. The leak is frequently due to a pressure that is a little too low, or conversely a little too high. Ideally, it should be between 1.5 and 1.8 bar;
  • A sealing problem : Not of the boiler itself of course, but of the seals. Indeed, with the many passages from hot to cold, the boiler contracts and then expands perpetually. Seals experience these variations and eventually loosen and leak. If they are not checked and tightened from time to time, they become deformed and no longer manage to play the role of sealing. Too worn, it will sometimes be necessary to change them. It is a very frequent and usual phenomenon;
  • A failure of the heating element : The heating body is the part that produces the heat and transmits it to the heat transfer liquid, which in turn transmits the heat to the radiators. Over time, the heating body can degrade and crack, causing a leak. While not of great concern, this leak is more of a degree of urgency in that, if faulty, the boiler will not produce heat. Depending on the season, this can be very problematic;
  • A faulty circulation pump : If it is blocked or broken, the water in the circuit is no longer properly propagated, and can then accumulate and leak by pressure. Most frequently, an unusual noise when the boiler engages will set you off;
  • An expansion tank to change : When filling is done very quickly, if you often have to add water to the circuit, and the pressure is regularly too low, then it is likely that the expansion tank is faulty, and that it or the origin of the detected leak. It will not necessarily have to change. It may simply be incorrectly adjusted, and require re-inflation.

How to react ?

Do not panic, a leaky boiler is not necessarily a boiler that gives up the ghost. It is possible, of course, but it is sometimes possible that a single part is defective on the equipment, or that following a maintenance, parts have been tightened incorrectly. Before reacting therefore, it is advisable to analyze where the leak comes from. This does not exclude calling on a professional technician, but everyone is able to carry out their investigation, if only to eliminate the impending disaster. Here are some tips to follow.

Check boiler pressure level

To do so, nothing could be simpler: the boiler pressure gauge is made for that. Moreover, on a daily basis, it will be better to check it from time to time. The pressure must never be lower than 1 bar, nor higher than 2 bar. If you notice a pressure slightly below 1 bar, it is too low. In this case, open the boiler tap to introduce more water into the circuit. You will then see the manometer evolve.

Conversely, if you notice a pressure slightly higher than 2 bar, the pressure is too high. In this case, cut off the water supply using the second accessible tap, and bleed the radiators. To do this, place an empty container under the bleed screw of the radiator closest to the boiler. Then loosen the bleed screw slowly and not completely. As soon as water droplets appear, tighten it, and proceed in this way on each of the other radiators, always from the closest to the farthest from the boiler to respect the supply circuit. The water is then evacuated and the pressure reduced.

Check seals

The inspection of joints should be an action carried out at least annually by any individual. To do this, nothing very complicated. It is enough to inspect the possible presence of moisture by touching the fittings. With a hand, you will have to try to tighten each of them, even if they do not leak, and wipe them with a dry cloth. After a few moments, if a seal was loose, the leak should stop. On the other hand, if one of them is defective, it should start dripping again.

In this case, you will have to make the change. For the most seasoned in DIY, the seals can be bought in a DIY store and can be changed without too much difficulty. It will be necessary to cut off the water supply to the boiler before removing the old one and installing the new one. Be careful to check several times, the days following the change, if no new leak is to be deplored.

Call a professional

If the leak has been brought under control by you, so much the better, it’s settled at a lower cost. However, it will be advisable to monitor a possible malfunction the following days. On the other hand, if these first checkpoints have not made it possible to detect where the leak is coming from, or how to absorb it in a lasting way, it will be advisable to call on an emergency heating expert. If the leak is very important, it will obviously be necessary to quickly cut off the water supply to avoid damage. Beware, however, of interventions on weekends, which can quickly be billed twice or even triple than on weekdays. Depending on the estimated urgency of the leak, it will sometimes be better to wait until Monday morning to make a phone call…

Boiler replacement

The lifespan of a boiler is about 15 years. This is not always the case, fortunately, but it happens that the professional declares the device too old, defective and to be changed. In this case, the question of new equipment arises. How much budget to devote to it? What type of equipment to choose? Besides, is it better to go back to a boiler? Or rather consider a heat pump type system? Here are some arguments to help you choose.

The consumption

Even if it means renewing your heating system, it will be good to study other equipment, and in particular the heat pump, which consumes much less energy. The biomass boiler will otherwise be one of the most efficient models. It only uses vegetable organic materials as fuel, in particular wood or wood derivatives. On the other hand, the wood stove will only offer heating, but not hot water. It could therefore be considered as a means of saving energy, but not as a single alternative solution.

The price

Obviously, whatever system is chosen, the cost of renewal will remain high. From an economic point of view, the electric boiler will be the most profitable. It will cost between 1000 and 1500 € for entry-level. The condensing boiler, reasonable but a little more expensive, will offer very good performance, for reduced energy consumption.

Investment aid

The renewal of a boiler for more efficient and less energy-consuming equipment makes it possible to claim state aid. The MaPrimeRénov’ aid of €1,000 may be granted to replace a fossil fuel boiler in favor of a heat pump or a biomass boiler. Also, it will be possible to take advantage of a zero-rate eco-loan over 5 years, the interest on which will be borne by the State. VAT may be reduced to 5.5% instead of 20%. Finally, it will be good to find out about the local aid that can be put in place.

Focus on prevention

To limit the risk of leaks and premature deterioration of the equipment, it will be essential to have the boiler checked annually. It is a legal obligation which is also the responsibility of the occupation of the accommodation, owner or tenant. A maintenance contract can even be taken out so that any intervention is covered. In general, care must be taken to regularly inspect the connections and the pressure in the circuit.

Leave a Comment