A heating device for electrically heating a heat transfer fluid

A heating device for electrically heating a heat transfer fluid, the heating device comprising:

• a housing delimiting an internal volume which comprises at least one circulation chamber delimited by an outer wall for circulation of a heat transfer fluid,
• the circulation chamber comprising at least a first internal space and at least a second internal space separated from each other, at least partly, by a partition with a passage formed so as to allow circulation of the heat transfer fluid there between, an inlet hydraulic connection member connected to the first internal space and an outlet hydraulic connection member connected to the second internal space,
• wherein at least one first electrical heating element is received in the first internal space of the circulation chamber and at least one second electrical heating element is received in the second internal space,
• wherein the heating device is configured for mounting and operation in a horizontal position in which the first internal space and the second internal space are arranged substantially on the same level with respect to the ground,
• wherein the outlet hydraulic connection member is arranged at the substantially top portion of the second internal space when the heating device is in the horizontal position.