The three pass heater is build with twice co-axial pipe coil. They build together a inner radiation and a outer convection heating surface.
Heat accumulation masses are according to the newest regulations of anti pollution.
The change from the outer to the inner pipe coil is made by a oil cooled reverse plate.
High efficiency near 88%.
The electrical heater is build as forced flow heater.
The electrical heating elements are built into a pipe system, which is flowed through with the thermal oil.