This is how the famous Zehnder Charleston Multi-column is made

During the first phase of production of a multi-column radiator, steel strips are wound into a coil measuring 1200mm to 1500mm in diameter and weighing over 2 tonnes. Steel tubes measuring 4 to 6 metres are used to create the radiator columns.

Production of the collector

The coils of steel are punched by a press to create the two halves of the collector. The two pieces are then welded together to form double-machined heads. These headers are then sanded and cut in half to create two collectors. These elements are then quality checked before moving onto the next stage.

Production of the section

The collectors and the tubes are now welded together and then ground to make neat joins. At each stage the sections are checked and quality controlled.

The sections are hermetically sealed and then immersed in a bath of water. Each section is then subjected to a pressure of 16 bar to check for leaks.

Assembly

The radiator sections are now connected to each other using tip-welding. Further testing then checks each radiator for leaks.

After testing, the radiator is suspended ready for the next stage in production.

The finishing touches

First of all the radiators are cleaned to remove any dust and grease. Next a base coat is applied using an electrophoretic technique in order to protect against corrosion and to give a perfect base. The radiator is then placed into a furnace, baking the primer on to the steel at about 180°C.

After sufficient cooling, the radiator is moved along the production line ready for powder coating. Powder coating is much more environmentally friendly than wet painting. Standard white radiators are automatically painted, whereas all other colours and finishes are manually sprayed.

The radiator is then returned to the oven where the powder melts evenly and gives the radiator a perfect finish that is resistant to shock and heat.

Before packing, each radiator is thoroughly quality checked once again and then up to 98% of radiators are packaged and wrapped using a fully automated system.