Weil-McLain has introduced the Ultra Boiler with PhD Technology. Two models are available: the Ultra 155, with a 93% AFUE, and the Ultra 230, with a 92.8% AFUE. The Ultra boiler's PhD Technology (Precision Hydronic Data) is an intelligent system that delivers precision hydronic heating and hot water needs, while maximizing efficiency by measuring and responding to the data parameters of a heating system. The Ultra requires minimal clearance and floor space, and can be used in floor-standing or wall-hung applications. Weil-McLain.