The Titan Package Steam Boiler Mocdel 'AS' is designed to the latest British standard 2790. The Boiler adopts the reverse-flame principle of combustion where the hot gases make 2 passes within the pressurised combustion chamber and the third and final pass through the fire tubes on its exit to the chimney.

The combustion chamber is supported by stay bars at its rear end. (It stands clear of the boiler drum back plate, thus giving rise the the wet-back design.) This design feature not only increases the heating surface, but also reduces unnecessary refractory-work.