Navien Combi Boiler Review Introduction:The Navien NCB 40 is a gas-fired, wall-mounted condensing boiler that is perfect for larger homes with multiple bathrooms. It has a high seasonal efficiency rating of 96% and an ErP A rating for heat and hot water. It also has a generous 7-year warranty.Features:Easy to installHigh-quality productAffordable price7-year warrantyFlue can be run up to 20 meters and the boiler can be fitted outsideComes supplied with a built-in filling loop and a free wired Opentherm wifi smart therm... May 24, 2017 Continue Reading