Electric Radiator Safety

Can I connect a more powerful electric element to the radiator?

The settings on the element are for temperature not power. A higher power element will just heat the radiator faster from cold, but they will reach the same maximum temperature anyway. 

We provide slightly less powerful elements, as Terma specifies that the output of the element should not be more than 10% of that of the towel rail. You could use the higher power element on low power but it is not advised as the warranty would not be covered for using an element outside of this 10% range.

Long story short – play it safe with the less powerful element – it should sufficiently heat the towel rail.

We supply correct elements for the electric radiators, thinking about your safety first.


Can the electric radiator explode from overheat?

The thermostat in the element will turn the power off once the set temperature is reached until the temperature falls below the set point.

With a higher power element, if the control system failed in such a way that the element went to full power the radiator would receive the full rated power of the element. The radiator would heat up until the radiator/system was getting rid of the energy being input by the element.

If the radiator was on an open system, if the energy was not dissipated by the radiator the water would begin to boil at around 100 degC. The steam would heat the water in the rest of the system which would eventually reach a steady state.

On a closed/pressurized system the boiling point of the water will be higher – (at 3bar around 130 degC, and at 7 bar 165 degC) . The radiator will increase in temperature until it is dissipating as much heat as the element is outputting, The temperature it could rise to would depend on the pressure relief valve on the system. A 3 bar relief valve would allow the radiator temperature to reach 130 degrees. If the radiator could not dissipate the element energy at this temperature the water would begin to boil, and dump the water/steam system relief valve . In either case when there was no more water to boil the element would simply burn-out like an electric kettle with no water.

On a stand alone towel-rail not connected to a central heating system it is good practice to fit pressure relief valves. (There are compact ones available which will fit in 1/2″ tapped holes which look very much like bleed valves or plugs) – this will prevent the pressure/temperature rising to such a point that the radiator explodes.

All this is unlikely unless the radiator is grossly overpowered.

If the element gets too hot due to the towel rail being too small then the element will shut itself off as a safety feature. It’s a great feature to have as it protects your towel rail and you.

Even with all the safety features, we still discourage from using too powerful elements as it not only won’t be covered by a warranty, but can damage/destroy your radiator.