Ray™ is a high-efficiency, low-mass fully condensing cast iron boiler. The residential unit can run on either natural gas or propane; no conversion kit is required. It delivers 40,000-199,000 Btuh at 92.7 percent AFUE. The boiler utilizes SmartCycle™ technology, an onboard digital monitoring and control device that learns the most fuel-efficient cycling pattern/firing rate based on actual usage once installed, and every unit adapts to its specific load demands. Its symmetric air/fuel coupled combustion system can automatically adjust to air pressure changes resulting from altitude. The boiler is down-fired, which according to the manufacturer, means less energy is required for operation and there is less opportunity for condensate corrosion, while the lower mass of the internal water content means faster recovery of temperature.

Mestek Inc., 260 North Elm St., Westfield, MA 01085; 413-568-9571; www.mestek.com