Thermal safety valve

How it works and what it is used for

Thermal safety valve 07/12/2023 21:12:23 Univectra d.o.o. ExpertFlame

Solid fuel boilers may get overheated during operation, mostly due to a power failure. The circulation pump stops while there is burning fuel inside the boiler, and the heating water temperature in the boiler starts rising very fast because the heat is not dissipated from the boiler. This danger can be prevented by installing a thermal relief valve that needs no electricity for its operation.

These small devices are used in heating systems to drain and/or cool the generator water when dangerous temperatures are reached, calibrated according to the model. This ensures the safety of the system.

Thermal relief valves are more commonly used in solid fuel boilers. They are positive-acting, which means that their use is guaranteed even if the temperature-sensitive element that should signal the valve to activate is defective. Even in this case, the system will activate to provide the necessary safety.

The valve only operates when a certain temperature is reached, which is detected by a sensitive element immersed in the system liquid. The element is able to move the valve shutter, which opens and allows water to flow out of the generator, while cold water enters to cool the system.

The action of the shutter triggers an electrical diverter which can either cut off the fuel supply to the burner or trigger the intervention of the make-up device. When the closing temperature is reached, the valve is automatically closed again.

Thermal relief valves can be installed vertically or horizontally, but cannot be installed upside down to prevent contamination from adversely affecting their operation.

The installation of the valves should be carried out respecting the direction of flow and should be entrusted to experienced and qualified professionals who can carry out the correct sizing. It is important that the valve be installed as close as possible to the boiler, i.e. on top of it or on a pipe within a maximum of one meter.

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