Our wall-mounted SL G3 residential condensing boilers convert natural gas or propane into heat with unprecedented efficiency. All residential models feature supply and return connections on both sides making them easy to install. Efficient internal layouts allow for easy inspection. With more interchangeable parts, 2 fans and 1 universal touchscreen controller, installing and servicing all models just got a whole lot easier. Multiplex racking and piping kits available for commercial models.