Altecnic / Caleffi 309 Series Pressure & Temperature Relief Valve 1/2

Altecnic / Caleffi 309 Series Pressure & Temperature Relief Valve 1/2" 90°C 10 Bar - 309400CST

The Altecnic / Caleffi 309 Pressure & Temperature Relief Valve - 309400CST is designed to effectively control and limit the temperature and pressure of hot water in domestic storage heaters. This essential safety valve ensures that water temperatures do not exceed 100°C, preventing steam formation. When the temperature or pressure reaches its set limits, the valve releases a sufficient amount of water into the atmosphere, ensuring that both temperature and pressure return to safe operating levels.

**How It Works:**

The valve features a thermostat compound within the temperature sensor that is submerged in the hot water storage heater. As the temperature increases, the compound expands, moving a thrust pin that activates the obturator, thereby opening the valve. This mechanism is set to initiate opening at temperatures exceeding 90°C. Regarding pressure, the obturator, which is countered by a spring, lifts when the pressure reaches its designated limit, fully opening the outlet. The pressure setting is predetermined based on the system's maximum permissible pressure. As the temperature and pressure decrease, the valve automatically re-closes within the specified tolerances.

**Product Specifications:**

  • Size: 1/2"
  • Connections: Male x Ø 15 mm with compression fitting for copper pipe
  • Materials: DZR
  • Medium: Water
  • Set Pressure: 10 Barg
  • Discharge Rating: 10 kW
  • Temperature Setting: 90°C
  • Probe Length: 102mm
  • Product Code: 309400CST

**Notes:** WRAS approved, CE marked

This high-quality pressure and temperature relief valve is an indispensable component for maintaining the safety and efficiency of your domestic hot water system. Ensure optimal performance and compliance with regulations by choosing the Altecnic / Caleffi 309 Pressure & Temperature Relief Valve.

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Other Products and Services from Flowstar (UK) Ltd

Altecnic / Caleffi 312 Series Safety Relief Valve 1/2

Altecnic / Caleffi 312 Series Safety Relief Valve 1/2" x 1/2" M x F 6 Bar - 312460CST

**Altecnic / Caleffi 312 Safety Valve - Model 312460CST** The Altecnic / Caleffi 312 Safety Valve (Product Code: 312460CST) is essential for safeguarding domestic hot water systems. This reliable valve is designed to protect hot water cylinders, boilers, and various components in heating systems. Each valve is carefully selected for its required set pressure, ensuring optimal performance. When the system pressure exceeds the preset level, the 312 Safety Valve activates, discharging excess pressure safely into the atmosphere. This critical function helps prevent dangerously high pressure within the system, protecting both the boiler and hot water storage cylinder, as well as ensuring safety for personnel nearby. **Specifications:** - **Size:** 1/2" x 1/2" - **Connections:** BSP Male Inlet x BSP Female Outlet - **Materials:** Brass - **Medium:** Air and Water - **Set Pressure:** 6 Barg - **Discharge Flow Rate:** 248.8 kg/hr - **Maximum Boiler Rating:** 144.6 kW - **Temperature Range:** +5 to +110 °C - **Product Code:** 312460CST - **Certifications:** WRAS approved, CE marked Choose the Altecnic / Caleffi 312 Safety Valve to ensure efficiency, safety, and compliance in your hot water and heating systems. Ideal for both residential and commercial applications, this valve is a critical component for maintaining operational integrity.
FSSCDF - Forward Acting Rupture Discs

FSSCDF - Forward Acting Rupture Discs

The FSSCDF Forward Acting Rupture Discs feature precision micro-scored sections that open in controlled petals, using four, six, or more radial score lines to ensure a clean, reliable opening while minimising the risk of petal separation. This design makes them particularly well suited for high burst pressure applications and for systems operating under cycling or pulsating conditions with gases or liquids, without compromising safety margins.

These discs respond to overpressure within milliseconds, opening fully without fragmentation, and are ideal for protecting safety relief valves. They support an operating-to-burst pressure ratio of up to 85%, offer excellent corrosion resistance, and can be further enhanced with an optional PTFE lining. In many applications, the discs can also withstand full vacuum conditions without additional supports, providing flexible installation options.

Key Specifications:

  • Sizes: 1" (DN25) to 36" (DN900)

  • Materials: Stainless steel, Alloy 201, 400, 600, 625, C276, Titanium

  • Burst Pressure Range: 2–413 bar g (30–6000 psi g), depending on size and material

  • Krl: 1.33

  • Tolerance: ±5% to ±20%

  • Operating Margin: Up to 85%

  • Temperature Range: –196°C to 600°C

  • Fragmentation: None – clean, petal opening

  • Use Under Valve: Yes

  • Corrosion Resistance: Very good

  • Linings: Optional

  • Holders: FSHI/A, FSHI/P, FSHI/F, FSHTC

  • Rupture Detection: Electrical, Magnetic, Inductive, Optical

  • Certifications: ASME (UD Stamp), PED (CE), ATEX EX II 2 GD

Flowstar UK Ltd

Flowstar (UK) Ltd

Wiltshire Road, Kingston-upon-Hull, East Riding of Yorkshire, HU4 6PA, United Kingdom

Flowstar (UK) Ltd is a leading global supplier of safety, relief, and reducing valves. With strong partnerships across major manufacturers, we deliver precise, reliable valve solutions tailored to your needs. Email enquiries to sales@flowstar.co.uk or call us on +44 (0)1482 601030.