The first thing to note is that cast iron radiators are not to be used as part of a secondary hot water systems (HWS) – they are only suitable for closed heating systems. All bush ends/caps for your Cast Iron Radiators will only be hand tight to allow customers to interchange if on a gravity fed heating system and will need fitting correctly when installed with PTFE tape.

A common cause of leaks is over tightening of the valve tails into the bush ends of the cast iron radiator. Over tightening will crack the bush. When fitting the valve tail in to the bush turn it finger tight then using a spanner turn it until there is only moderate resistance. Using a 4” spanner it is difficult to over tighten. A thread sealant must be applied to the radiator end caps and to the valve tail threads to get a water tight seal. LSX sealant available at all plumbers’ merchants is recommended. PTFE tape is an acceptable alternative. The torque from an 8” adjustable spanner will be sufficient to create a good seal.

All valves and air vents/bleed valves to be fitted with LSX sealant or PTFE tape.

No caustic/corrosive/acidic plumbing compounds or liquids are to be used on or in any part of our radiators, our valves or connections including aggressive flushing agents. If required, the system should be flushed with clean water only. The water in the system must be neutralised correctly following the use of any compounds etc if required using appropriate crystals or similar. If caustic and/or corrosive compounds (liquid or other) have been introduced into the system resulting in subsequent damage to seals/gaskets, any guarantee offered will be invalid. When a chemical cleanser is used it must be thoroughly flushed from the system. We recommend the use of Fernox F5 for power flushing and F1 rust inhibitor. Unlike other chemicals these products are not acid based and should not affect seals. After treatments the water should be checked for a neutral PH between 7 – 8. System design, flushing and dosing must be in accordance with BS 5449, 1990, BS EN 12828:2003 and BS 7593.

Following this procedure the system must be closed with a sufficient corrosion inhibitor suitable for the water quantity in your system. Dosing tools should be used to ensure the minimum correct levels of inhibitor are present at all times to prevent corrosion and should take into account the particular metals within the system. Appropriate inhibitor should be used in conjunction with manufacturer’s instructions and appropriate quantities must be used for the water content of the system.

We recommend you choose a qualified and experienced plumber or heating engineer to install your cast iron radiator.