Heating Safety Valve

This component is essential for the proper functioning of the boiler. The heating safety valve is used to control excess pressure; once a certain limit is reached, it begins to release.

It consists of a passage regulated by a membrane pushed by a spring. The spring of the safety valve in question is calibrated to withstand a pressure of 3 bar. The boiler safety valve is a critical component of the heating system, its main function being to monitor the pressure inside the boiler and automatically release excess pressure in case of emergency.

The safety valve is usually located at the bottom of the boiler. When the pressure inside the boiler exceeds the predetermined safety level, the valve opens automatically, releasing excess pressure and preventing leaks in other parts of the system.

The safety valve is a critical component of the boiler and must be tested regularly to ensure its proper functionality. There are several factors that can cause an increase in pressure inside the boiler, such as excessively high temperature, reduced water flow, a faulty filling valve, or scale buildup within the heating system.

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Quality of Safety Valves

There are different types of safety valves available on the market, each specific to different boilers. The most common ones have a 1/2-inch connection. Then there are valves with a housing for a 1/4-inch pressure gauge connection. This pressure gauge connection needs careful consideration, as it may require an adapter if the gauge has a gas thread. Sometimes this adapter is seen in older boilers.

Main Causes of Leakage

Typically, these safety valves are stressed by high pressures. It is important to replace them if they leak, but the task is to find the causes that led the valve to open. Normally, safety valves open when the heating expansion vessel is deflated. This vessel is inflated during each maintenance because its essential task is to cushion the excess pressure caused by temperature increases.

Regarding pressure, another factor stressing this valve is the amount of water. The water in the system depends on the number of radiators or rooms served by radiant panels. Boilers usually have an 8-liter expansion vessel. However, this may not be sufficient, so an additional heating expansion vessel is used. The supplementary expansion vessel helps cushion the pressure in large systems; I consider a system to be large when it exceeds 180/200 m².

Another factor contributing to the failure of this valve is dirty radiator systems. Especially in systems with cast iron radiators, dirt and sludge make it difficult for this valve to function properly. When the valve allows even a drop to pass through in dirty systems, its sealing capability is already compromised. Therefore, as a preventive measure, cleaning the system is not a bad idea to reduce the risk of leakage in this and other valves.

Preventing Leaks

To prevent leaks in this valve, regular maintenance and careful regulation of boiler pressure are sufficient. The main causes of leakage are a deflated expansion vessel that increases pressure beyond 3 bar. Subsequently, a diligent technician should, in case of leakage, not only replace the valve but also investigate the reasons for its opening.

For preventive purposes, we can:

• Regularly clean the boiler
• Equip the system with an additional expansion vessel
• Clean the heating system every approximately 15 years