Cast Iron Radiator Installation

Modern cast-iron radiators are made to the highest quality, and many are custom-built to a customer’s personal specifications before being pressure tested to make sure they are perfectly watertight. Because of this, it is vital that radiators are not mishandled when being delivered and installed, or leaks and other faults can occur. These simple instructions will ensure that your new radiators stay in perfect condition:

Delivering your radiators: Safe lifting and unloading

Because of the great weight of cast iron radiators, they should never be unloaded alone once they are delivered by pallet courier. Always stay within HSE lifting guidelines.

The pallet supports the radiator’s full length, but this support is removed once the pallet goes, meaning that the radiator must remain held upright at all times. Carrying it flat without support to the middle or dragging it runs a severe risk of causing leaks due to strain on the watertight gasket seals. This strain becomes worse the longer the radiator’s length. Many people use short pieces of sturdy wood placed between the two end sections as makeshift handles.

Custom painted cast iron radiators

These radiators are carefully packaged for transit and this keeps the risk of scratches and other damage to a minimum. The greatest risks to the paintwork come when unpacking, handling and installing the radiators, which is why a small pot of paint for touching up scratches is supplied.

Hand Polished Cast Iron Radiators

Hand Polished Cast Iron Radiators are carefully hand polished to reveal the original cast iron surface of the radiator, leaving a beautiful metallic finish. Because the bare metal is exposed to the air, however, it is essential to care for these radiators carefully to prevent the formation of rust spots. This can be done by polishing the radiator every six to eight weeks using a soft cloth sprayed lightly with WD-40. Because the part of the radiator facing the wall is particularly hard to keep clean in this way, it remains unpolished.

When Installing Your Radiator

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. When the radiators are installed, the entire HWS needs to be cleaned and flushed out to get rid of any contaminants or other debris. After this is done, close off the system with an effective eminence water treatment, such as Fernox, to stop future rusting or other corrosion. However, it is important to note that corrosion inhibitors need to be compatible with the metals and other materials used in the HWS as a whole.

Be sure to apply the correct amount of chemicals when treating the water system and ensure that all flushing and dosing is in line with BS 5449, 1990, BS EN 12828:2003 and BS 7593. We recommend that you avoid using water softeners on your HWS as these can lead to damage to the watertight seals on the radiators.


Valve Installation

When installing thermostatic valves, it is important not to over tighten the valve tails into the base sections of the radiator (the bottom bushes), which is a major cause of leakage because the bushes will crack. First turn the valve tails by hand until they are as tight as you can make them, before using a 100mm spanner to further tighten them until you encounter moderate resistance. Using a larger spanner increases the risk of over tightening. During installation, apply a thread sealant, such as LSX (available from all plumbers’ merchants) or PTFE tape to make all valves extra watertight.

With normal usage, you shouldn’t need to unscrew the bottom bushes, but if it becomes necessary then retighten them as gently as possible, while maintaining a decent seal. You should not need any spanner with greater torque than a 200mm adjustable spanner.

Note that the male thread on the bush (the one that screws into the radiator casing) on the bleed valve side of the radiator is a left hand thread, needing to be turned anticlockwise to tighten it. The female threads (the threads that the inlet or outlet valve or bleed valve screws into) are a standard right hand thread, needing the screws to be turned clockwise. This is also the case with the threads on the other side of the bleed valve.

Two other things to be aware of during the installation process is that cast iron radiators’ thermostatic valves feature frost protection and are not bidirectional.

Installing Wall Stays

When putting the wall stays in place, these need to be clamped between two of the radiator’s adjacent rear columns. Cut the long threaded rod to the correct length so that it can be sufficiently close to the wall.