HOW A HEATER MATRIX WORKS
1 Typical classic matrix
A typical classic coolant-fed heater matrix is often a small, chunky radiator featuring an inlet and outlet tank either side of a radiator core. The core is made from a network of narrow copper or aluminium tubes with tiny cooling elements attached. Cool air is drawn across these elements by the fan and heat thus transfers to it. The now-warmed air is blown through trunking and directed wherever it is needed.
2 Early type saloon heaters
Some of the earliest types of saloon heaters were proprietary units, made by manufacturers such as Smiths or Clayton and could easily be added to almost any water-cooled vehicle. Although they lacked sophistication and only recirculated saloon air, they were a massive step forward for incar comfort, bringing shin-singeing warmth to front seat passengers and a waft of warm air to the windscreen.
3 Typical classic heater/demister system
The heating and demisting system is relatively simple in many classic cars. Fresh air is drawn in from outside – often through a grille in the scuttle – and passed over the matrix. The warmed air is then blown out of the heater box and directed either to the screens or to the saloon by a driver operated flap. A modicum of heat graduation is offered by the inclusion of a variable valve regulating the amount of coolant flow and so altering the ratio between incoming cool air and matrix heat.
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