Safety valve 2115 G 1/2 inch 8bar brass 2115.15.201

Pressure protection in closed water systems

Safety valve 2115.15.201 is a membrane shut‑off device that opens automatically when the set pressure is exceeded – in this case 8 bar. It is mainly used to protect closed domestic hot water heaters, where heating causes volume expansion and pressure rise. Without such a valve the installation may be damaged, and in extreme cases the tank may fail.

Which installations is it intended for?

It can be used in drinking‑water systems as well as with other non‑corrosive liquids, at temperatures not exceeding 110 °C. In practice this means it is ideal for central heating boilers, water heaters and heat exchangers in closed installations. It is not suitable for steam or gas systems – its design is optimized solely for liquids.

The version with a stainless‑steel seat (designated 2115N) allows this element to be replaced without replacing the entire valve – a service key 4807.00.911 is sufficient. This solution considerably extends the device’s service life, especially in installations with hard water or frequent opening cycles.

How it works and how to install it?

The valve uses a membrane as the pressure‑sensing element – it does not use a piston or spring, which eliminates the risk of blockage by deposits or contaminants. When pressure rises the membrane deforms and opens the flow through the outlet. When pressure drops it closes automatically.

Installation should be performed vertically, with the inlet at the bottom – as specified by the manufacturer. Horizontal or inverted mounting may lead to improper operation or faster membrane wear. The connection is G 1/2", which corresponds to DN 15 – the standard for most domestic heaters.

It is worth noting: the 8‑bar setting means the valve opens at a pressure higher than 8 bar – not at 8.1 bar, but when the pressure exceeds the value designed for this membrane (usually with some hysteresis). Therefore it is recommended to select a valve whose setting is at least 20 % lower than the system’s maximum allowable working pressure.

Additional information?

• Material: The bodies are made of brass – corrosion‑resistant, but not suitable for aggressive chemical environments.

• Compliance: Meets the requirements of DIN 1988 (part 200), TRD 721 and AD‑Merkblatt A2.

• Compatibility with glycol: It can be used in water‑glycol solutions – but the glycol content must not exceed 50 %.

• Visual inspection: The valve cover carries a seal marked “8 bar” – allowing quick verification of the setting without disassembly.

• No service required under normal operation – however, if it drips after the heater is turned off, the issue is more likely an installation error (e.g., lack of expansion) rather than a valve failure.