Safety valve 8115 3 bar 1/2 inch, solar 8115.15.151

Protection of solar systems against overpressure

Membrane safety valve 8115.15.151 opens at a pressure of 3 bar, preventing damage in installations with solar collectors, where improper heat dissipation can lead overpressure. It is intended for systems filled with water, steam, inert gas or a water‑glycol mixture – up to a maximum of 50 % glycol concentration.

The valve is installed vertically, with the connection at the bottom – which ensures proper membrane operation and eliminates the risk of blockage by deposits. It does not require a capillary or additional control elements – it operates solely based on pressure differential.

For the installer – simplicity and compliance with practice

In practice a 1/2" (DN15) valve is sufficient to protect collectors with an area up to 50 m² – which corresponds to a typical domestic system. A setpoint of 3 bar is commonly used in solar installations, where the working pressure does not exceed 1–2 bar, and the safety margin must be sufficient for accidental overheating.

Operating temperature up to 160 °C allows safe operation even during prolonged stagnation – e.g., in case of pump failure or system shutdown in summer. Compared with other models (e.g., 1915 with a maximum of 140 °C), this valve has a higher thermal limit – which is important in systems with large thermal capacity or without heat discharge.

What does this mean in practice?

• If the system overheats and pressure rises above 3 bar, the valve automatically opens and releases the excess.

• When pressure drops, it closes automatically, without the need for manual resetting.

• No maintenance required – the membrane has no moving parts except the membrane itself.

• Certified according to test type UDT 42-C-04/imp – confirming its approval for use in heating installations in Poland.

No need to connect it to sensors or controllers. It works as a “mechanical guard” – simple, reliable, maintenance‑free.