If you use the motor car as a metaphor for your domestic central heating system, the engine of the car would be the boiler. The wheels and tyres would be the radiators as the conduit that transfers the energy to your home, ensuring the system delivers on its potential and using the input energy (gas or oil) effectively. Beside the boilers, which normally attract a lot of attention, a well designed and positioned set of radiators can have a major impact on the output and efficiency of a typical domestic central heating system.
It might come as a surprise that those sleek looking stainless steel radiators offered by most UK plumbing and heating merchants date back more than 150 years. The first radiator was registered as a patent in 1855 by Franz Sangalli, a German engineer. In effect, despite considerable visual differences, the main working structure of the radiator is the same as the ones registered initially by Mr. Sangalli. The radiators are effectively a hollow case made of metal, shaped as a flat box and attached to the wall to maximize radiation of heat into the room.
UK made radiators are typically made of sheet steel with fins to emit more heat. The heating liquid, normally water, is pumped into the radiator. The hot liquid loses its heat into the room and as it cools off it drops to the bottom of the radiator and eventually is pumped out via the return valve. The air around the radiator heats up and consequently rises to the top of the room, drawing in cooler air. This convection effect keeps a circulation of heating within the room and constant heat within the home.
Radiators, though tried and tested over many years, still suffer from typical problems from time to time. One of the most common problems is the air pockets that develop within them. These small pockets can be a result of tiny bubbles of air creeping into the sealed central heating system through tiny cracks. Professional central heating installers minimise the risk of such cracks by using compression fittings or other solution to ensure the connection points are free from potential cracks.
An alternative explanation for the bubbles within the circulation loop is that they are the result of a chemical reaction that occurs when copper piping and other metals are in continuous contact with very hot water. Such reactions lead to tiny bubbles of hydrogen that float within the system and find their way to the upper most point of the closed loop heating system. This explains why it is often the top of the radiator that remains cold (as it is filled with gas rather than hot water). Is such cases it is recommended to bleed the radiator from the bleeding valve at the top of the radiator, using a special bleeding key. Such keys can be found in all major DIY stores in the UK.
Radiators may suffer from another problem due to their chemical make. As hot water comes in contact with iron and other metals the reaction releases not only gases but also other chemical deposits which clog the system and reduce its performance. This problem is more acute with older systems and in extreme cases can make the central heating system completely in-effective.
Modern plumbers reduce the risk of such corrosion by adding a corrosion inhibitor to the mix of liquids within the central heating loop. In addition most plumbers these days power flush the system before filling it up to remove any such deposits and sludge. It is important to notice that power flush can remove debris even from brand new systems. Such debris can be a result of the metal workings and the manufacturing process of the radiator units or the copper piping.
Author: Robert BonelloThis author has published 2 articles so far.