Distribution of heat in an electric radiator

The electric radiator with a heating medium liquid is fitted with a heating element in one of the collectors as a source of heat. The heating medium is heated by the hot heating element. This causes the heating medium to raise up, and as a consequence this starts the circulation of the heating medium throughout the radiator. While moving up, the hot particles of the heating liquid mix with particles of the cold liquid (so-called diffusion phenomenon), causing the heating medium to move along the horizontal pipes of the radiator. The cooled liquid drops to the lower parts of the radiator to rise again after being reheated (see picture).

Distribution of heat in an electric radiator

In conclusion, the collector directly connected to the heating element will always be the warmest part of the radiator (especially its upper section), while the lower pipes will always remain cooler. Such a phenomenon is absolutely standard.

Note:
If the heating element is installed directly into the radiator collector (not through a T-piece or valve), the two lowest tubes of the radiator will remain cold.