Why the boiler stopped heating water – reasons and solutions

For homeowners, particularly in the winter, it can quickly become a frustrating problem when the boiler stops heating the water. In addition to interfering with our everyday activities, a broken boiler can cause discomfort and increase energy costs. Knowing the causes of this widespread issue will enable you to identify the problem quickly and choose the appropriate course of action.

A boiler may stop heating water for a number of common reasons. It might be the result of a broken thermostat, a heating element that isn’t working properly, or even a blocked pipe or valve that isn’t allowing water to flow. Occasionally, the problem could be as straightforward as a tripped circuit breaker or a power outage. The first step in solving an issue is determining its underlying cause.

Thankfully, it’s possible to fix a lot of boiler problems on your own without hiring a professional. Minor problems can frequently be fixed with basic troubleshooting techniques like checking the thermostat settings, making sure the boiler is getting power, and looking for any obstructions in the pipes. To guarantee the efficiency and safety of your boiler system, you must, nevertheless, seek assistance from a certified heating engineer if you are unable to diagnose or resolve the issue on your own.

Principles of operation

The two circuits that gas boilers typically have are for heating and water heating. Dual-circuit appliances are a grouping of multiple components that work together to provide a particular system function. Thus, the water unit supplies water and maintains the required pressure in the mains, the smoke exhaust unit emits combustion products into the environment, the control unit keeps an eye on the operation of all boiler systems, and the gas unit ignites and burns the burner, allowing heating the heat-conducting liquid.

Water is pumped into the system through the heat exchanger tubes by a pump when the unit is turned on. The gas supply valve opens and ignites the burner as soon as the liquid enters the water assembly. Temperature sensors track the heat exchanger body’s consistent heating process.

Crucial! Sensors are used to control the heating cycle. The sensors send an impulse to the control module to restart heating the water when the temperature falls below a set point.

The flow sensor is activated when hot water flows through the faucet. It sends a signal to the board, which activates the three-way valve and turns on the water supply heater.

The main problems why the boiler does not heat water

Boiler malfunctions are typically discovered during the heating season, when the appliance’s two circuits are running. Owners of wall-mounted gas boilers, like Ariston, deal with two major issues:

• all boiler systems are working, the device is switched on, but heats water poorly or does not heat at all;
• The boiler does not start and, as a consequence, no hot water is supplied.

Every one of these issues has unique roots and remedies. Understanding what causes malfunctions and what causes them to occur is essential to eliminating them.

Prior to determining the reasons behind the malfunction, you should read the instructions, consult the handbook, and make sure the device is connected and set correctly.

Kindly take note! A diagnostic system that finds problems and shows an error code on the display is a feature of modern gas boilers. You can figure out the codes with the aid of the unit manual.

The following common malfunction causes should be taken into consideration if all requirements and conditions are met:

• Clogging. Experts say that using unfiltered working fluid increases the risks of heat exchanger pipe clogging. Limescale reduces its thermal conductivity, which causes the unit to operate with excessive energy consumption. In this case, the optimal temperature regime is not reached even with continuous operation of the device. Due to the lime scale deposited inside the heat exchanger pipes, the metal undergoes corrosive changes, which can lead to its rupture.
• Defective pump. Circulation of the heat transfer medium can be stopped due to air accumulation, a so-called air lock in the pump. The second cause of pump malfunction can be the rotor, which is jammed. A circulating pump that has stopped functioning can lead to overheating of the gas boiler.
• Flow sensor stalled. Inside the boiler there is a sensor in the form of a turbine resembling a small fan. When the turbine spins inside the sensor, the fluid current generates an electrical impulse that is fed to the control unit. In this way, the electrical system realizes that it needs to warm up the heating medium.
• Three-way valve stuck. Such a malfunction will not allow you to switch the water supply from heating to DHW. A blockage in the valve can occur due to a clog, either in the part itself or in the gas hose or filter.
• Insufficient pressure. If the volume of liquid in the system does not create the required pressure, the water supply valve does not open, which leads to burner ignition failure.

Possible nuances

There are numerous gas wall-mounted boilers from various manufacturers available on the market today. All models operate on essentially the same principle, but each brand has unique characteristics that may be related to the reasons behind malfunctions and, consequently, inadequate water heating.

• "Ariston" – Italian brand, which is characterized by reliability. Boilers of the brand are adapted to domestic engineering communications and operating conditions. The most common cause of malfunctions – hard water, which contributes to the formation of clogs in the heat exchanger and circulating pump.
• "Navien" – Korean autonomous gas boilers. They are easy to operate and efficient. The peculiarity of the modification is the presence of two heat exchangers and the absence of a control panel on the body. The reason why the boiler "Navien" badly heats hot water, can be a stoppage in the operation of the equipment. The culprit is the air pressure sensor, which in the presence of a back draft in the chimney assembly signals the control board, which closes the gas supply valve to the burner.
• "Vaillant.". German quality is fully reflected in the units under this brand. As the appliance is of European origin, the most common problems are its heat exchangers, which are clogged due to the improper quality of the conductive thermal fluid.
• "Baxi" – another representative of Italian manufacturers of autonomous heating equipment. It has simple and reliable boilers. The main reason why "Baxi" does not heat water, as noted by experts in the service of such units, is a factory defect, which is sometimes found in the model line of this company.
• "Arderia" is a South Korean manufacturer. He has provided a certain algorithm for controlling the heating equipment. Incorrect settings can be the answer to the question of why the boiler stopped heating water.
• "Proterm" – a subsidiary of the German company "Vaillant". When operating these boilers it is necessary to monitor the quality of the heat-conducting fluid, use cleaning filters to prevent clogging of the heat exchanger.
• "Buderus" – another "German" in the domestic market of autonomous heating equipment, which has proven itself with a positive side. As with all Europeans, malfunctions can be caused by the formation of lime scale inside the heat exchange system, as well as clogging of the working fluid flow sensor.

It can be very annoying and frustrating when your boiler stops heating the water. This problem may have a number of causes, from straightforward solutions to more complicated issues requiring expert care. Knowing these causes will enable you to identify the issue and choose the best course of action with speed and accuracy.

A broken thermostat is one of the most frequent causes of a boiler not heating water. It’s possible that a malfunctioning thermostat won’t tell the boiler to heat the water to the appropriate temperature. Sometimes this problem can be fixed by verifying that the thermostat settings are accurate. The operation of your boiler can be restored if the thermostat needs to be replaced.

An issue with the boiler’s ignition system or pilot light could also be the cause. The boiler cannot ignite and heat the water if the pilot light is out or if there is a problem with the ignition system. In these situations, the issue can be resolved by relighting the pilot light in accordance with the manufacturer’s instructions. It’s best to get professional assistance to identify and resolve the problem if the pilot light keeps going out or if there is a problem with the ignition system.

There may also be problems with the water flow or pressure in the boiler that result in insufficient hot water. An obstruction in the system or low water pressure can stop the boiler from heating water effectively. These problems can be avoided with routine boiler maintenance and inspection of the water flow and pressure levels. It’s critical to take quick action to fix any pressure changes or decreased water flow if you observe them in order to keep your boiler operating efficiently.

In conclusion, there are a number of reasons why a boiler might not heat water, such as problems with the thermostat, the pilot light or ignition system, pressure, or water flow. Maintaining an efficient boiler and guaranteeing a steady supply of hot water for your home requires routine maintenance, prompt troubleshooting, and professional help when necessary.

The inconvenient and frustrating thing can happen when your boiler stops heating the water. This issue may be caused by a number of factors, from straightforward solutions to more complicated issues. It might be caused by a broken pilot light, an inoperable thermostat, or even mineral buildup clogging the system. Checks and maintenance on a regular basis can help avert these problems. Don’t worry if this is an issue for you! Solutions range from do-it-yourself tasks like relighting the pilot light or checking the thermostat settings to contacting a professional for assistance with more complex problems. You can make sure your boiler keeps operating effectively and your house stays warm and comfortable by acting quickly and performing routine maintenance.

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