Caleffi 309473 CST 1/2″ Series 309 Pressure and Temperature Relief Valve 90°C 7 Bar WRAS Approved for Unvented Systems
Caleffi 309473 CST Series 309 Relief Valve provides dual protection at 90°C temperature and 7 Bar pressure with 1/2″ connection—WRAS approved for unvented storage systems.
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- Estimated Delivery: For most items (over 99% of our products), orders placed before 3pm on working days will be dispatched the same day with our Fast DELIVERY 1st class service. For the rare items not immediately in stock, dispatch may take 1-3 working days after receiving your order. If your order cannot be dispatched the same day, we will notify you via email.
- For boilers: We aim to dispatch on the next working day. However, in some cases, it may take 2-3 working days to dispatch. Rest assured, we will always strive for the fastest possible turnaround.
The Caleffi 309473 CST Pressure & Temperature Relief Valve is engineered for safe pressure and thermal regulation in unvented hot water storage systems. Set to discharge water at 90°C or when pressure reaches 7 Bar, this valve plays a critical role in protecting domestic cylinders from overheating and over-pressurization.
With a 1/2″ connection, the valve is compact and easy to install. Certified by WRAS, it complies with UK water safety standards and is approved for use in sealed domestic systems. Its high-performance brass construction and 10kW discharge capacity ensure consistent reliability and safety under demanding conditions.
Ideal for maintenance, retrofitting, or new cylinder installations, the 309473 CST Series 309 valve delivers compliant system protection and long-term performance in a compact format.
Key Features
• Dual Safety Protection – Opens at 90°C or 7 Bar to prevent overheating or excess pressure
• WRAS Approved – Certified for use in UK domestic water systems
• Compact 1/2″ Connection – Easy to install in standard unvented cylinders
• Robust Brass Construction – Designed for durability and consistent performance
• PED Category IV Rated – Built for pressure safety and compliance with European standards
Applications
• Unvented Hot Water Storage Systems – Prevent overheating and pressure spikes in domestic cylinders
• Residential Cylinder Installations – Ideal for new systems or replacing old safety valves
• WRAS-Compliant Plumbing – Meets UK regulatory requirements for sealed water systems
Technical Specifications:
| Feature | Details |
|---|---|
| Brand | Caleffi |
| Product Code | 309473 CST |
| Connection Size | 1/2″ |
| Temperature Setting | 90°C |
| Pressure Setting | 7 Bar |
| Maximum Pressure | 10 Bar |
| Medium | Water |
| Discharge Rating | 10kW |
| PED Category | IV |
| Approval | WRAS Approved |
| Manufacturer Code | 309473 CST |
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