How Does A Radiator Work

Why your car's heater won't work

In the chilly weather we’ve had recently we have had a few complaints about heaters not giving enough heat.

OK, heaters can fail, but more often than not it’s the thermostat giving trouble.

A far from mellow fellow came in last week, rubbing his hands and using colourful expletives to describe the shortcomings of his car’s heater.

He was especially vexed because he had apparently had a new heater fitted “not too long ago” whatever that means.

He said the needle reached mid-position around town, but on the open road it took a long time to get to normal operating temperature, which implied a faulty thermostat rather than the heater itself.

The thermostat is a very simple but effective control system, being a temperature-sensitive valve that remains closed until the engine reaches operating temperature.

As temperature increases the thermostat opens and allows coolant to be circulated through the radiator for cooling.

When the coolant falls below operating temperature, the thermostat closes restricting coolant circulation to the engine block, cylinders head and car’s heater. A bypass provides a passage for coolant return to the pump.

When a thermostat fails in the open position the engine does not overheat as it would if it failed in the closed position.

It reminds me of the good old, bad old days when cash was short. If a thermostat failed and the engine overheated, we simply chucked it away and ran the car without one.

No heating of course, but no more overheating either.

In our grumpy friend’s case, a new thermostat was all that was required. So, before thinking about buying a new or reconditioned heater, check the connections, the drive belt and the thermostat.

Testing a suspect thermostat is simple. Drain the cooling system and remove the thermostat. Check with the manual the temperature at which it should open.

For example, the manual might say it opens at 80 to 84 degrees Celsius and will be fully open at 95 degrees Celsius.

To test, suspend the thermostat in a container of water and heat the water and with a thermometer check the opening temperatures against the figures in the manual.

How Does An Oil Filled Radiator Work?

An oil filled radiator is a convenient way to spot heat any area of a building that tends to be chilly. As an alternative to kerosene, halogen, or gas heaters, these radiators provide a safe and quiet heat source wherever one is needed. As portable space heaters, they offer a way to help curb high utility bills during the winter.

So how does an oil filled radiator work? Each unit contains a special heat-efficient oil inside, which is then warmed with electricity when plugged in and switched on. The heated oil circulates through the radiator coils and fins to generate warmth through the process of convection, which allows the transfer of heat through a liquid. Cold air that is heated by the warm fins then rises, drawing in the air below it, and this process repeats itself. Sealed within the radiator, the oil becomes warm but never burns, and therefore never needs replacing or refilling, allowing for efficient operation. Lacking fans to circulate the air, oil filled radiators are practically silent. Their heat-retaining abilities allow them to continue warming an area for some time even after they are switched off.

Because of the oil ‘s high boiling point, it safely remains in liquid form even when the radiator is on full power, and this means the unit does not have to withstand high pressures. Since the oil will retain its heat for some time, these radiators will often keep an area warm on a very low setting. Oil filled radiators typically have a low surface temperature, but utilize a large surface area to heat a room quickly and maintain a certain temperature. Many models have thermostats to help reduce operating costs, automatically shutting off when a specified temperature is achieved, and some have programmable timers for more versatile heating options.

Oil filled radiators require virtually no maintenance and are safer than many other types of heaters. They lack the odors generated by gas and kerosene heaters, and their fire risk is much lower. Although not normally hot enough to burn, they do have safety covers in case of curious pets or children, and an automatic shutoff will be triggered in case of overheating or tipping.

Another advantage of oil filled radiators is their portability, although wall-mounted units are also available. Many are quite compact and lightweight, which makes transferring them to a different area easy. Some are even made to fit unobtrusively under a desk and require no more than 40 watts of power to operate; this allows them to use the same circuit as a computer, for example. This also makes them convenient for heating a small personal space in rooms that are shared with other people. Larger radiators may heat up to 150 square feet, and many of them are on wheels for easy transport.

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