The BWF series boiler is a cast iron gas fired boiler designed for use in forced hot water heating systems. The BWF is intended for installations where a usable chimney is not available. The BWF is normally vented using an approved vertical or horizontal AL29-4C stainless steel venting system, which is not included with the boiler. If a suitable chimney is available, the BWF series can be vented into it using an optional BWF Category I Vent Kit available from Crown. The BWF requires an adequate source of clean combustion air in the boiler room. The BWF boiler is not designed for use in gravity or “open” heating systems.