R&T Bottom Entry Air Gap Cistern Fill Valve — 1/2" Brass Shank
The R&T Bottom Entry Air Gap Float Valve is an authentic OEM replacement cistern inlet fill valve manufactured by R&T (Xiamen R&T Plumbing Technology Co., Ltd.), one of the world's leading primary sanitaryware component specialists. Fitted with a heavy-duty 1/2" BSP solid brass threaded tail, this valve eliminates the risks of cross-threading and overtightening fractures common with plastic shanks. Built with an integrated Type AG air gap compliant with BS 1212-4 and the UK Water Supply (Water Fittings) Regulations, it provides essential physical backflow prevention to keep mains drinking water safe from contamination. Engineered with delayed-action filling and an enclosed float design, it delivers smooth, quiet operation across low- and high-pressure systems.
Identification Guide:
Brand / Manufacturer: R&T (Xiamen R&T Plumbing Technology Co., Ltd.) | Model Series: A2420 / Universal Air Gap Series | Entry Type: Bottom Entry (Base of Cistern) | Thread Size & Material: 1/2" BSP Solid Brass Shank (~20.9mm OD) | Backflow Protection: Type AG Air Gap (BS EN 1717 / BS 1212-4) | Operating Range: 0.2 bar – 16 bar
Key Features
- Solid Brass Threaded Shank: Heavy-duty 1/2" BSP brass tail resists cross-threading and cracking when tightening supply connections.
- Type AG Backflow Prevention: Certified air break design prevents back-siphonage into potable water supplies without requiring separate check valves.
- Delayed-Action Filling: Holds water delivery until the flush cycle completes, preventing clean water from escaping directly down the pan.
- Telescopic Height Adjustment: Sliding vertical stem extends to match compact, standard, and tall cistern configurations.
- Acoustic Quiet Fill: Precision-moulded internal diaphragm reduces refill rush and eliminates hydraulic water hammer.
- Limescale-Resistant Build: Engineered from high-grade technical polymers (POM) for durability in hard water areas.
Installation & Compatibility Guidance
Designed strictly for bottom-entry toilet cisterns where the cold water supply pipe enters vertically through the bottom base hole of the tank. R&T valves are factory-fitted as standard OEM equipment across numerous UK trade and retail bathroom suites (including suites from Cooke & Lewis, GoodHome, VitrA, Tavistock, Bathstore, and Wickes). Ensure the cistern's overflow weir sits at least 25mm below the valve's air gap spill slots to maintain full UK Water Regulation compliance. Always flush supply pipes to clear debris before final connection.