The boiler sections are assembled with beveled, surface profiled push nipples for long, trouble-free watertight operation. Boiler flue ways are manufactured to be gas tight with tongue and groove section design and elastic, high temperature resistant sealing rope. This seal is fully pressed into the groove during assembly to allow positive pressure operation. A permanent dry door gasket ensures repeated positive sealing of the full swing burner door. Because flue gases cannot escape through the seams between boiler sections, the boilers are able to retain heat more efficiently.
Buderus developed a full three-pass system which increases the efficiency of the boilers. With single-pass boilers, the flue products have only one chance to heat the water. Buderus three-pass boilers triple this opportunity. The unique way heat flows through the G215 boiler allows the water to be heated three separate times. The full 3" thick thermal insulation helps to maintain a higher water temperature even after the boiler has gone into standby mode. The distinctive chamber design of the Buderus G215 also allows for nearly silent operation.