The Crown KSZ125 is a great choice for residential heating when chimney-venting is desired. Known for high reliability, this oil-fired boiler features a rugged wet base heat exchanger for maximum accuracy in water heating. Its dependability is bolstered by high quality parts, including Honeywell operating controls. When occasional maintenance does need to be performed, the KSZ125's easy-to-remove split jacket and swing-open burner door make upkeep a breeze. Product Features Rugged Wet Base Wet Base boilers surround the burner with water, allowing for more accurate water heating. Furthermore, ventilation installation is more flexible with this type of base. Factory Tested Honeywell Control System Honeywell is a byword for outstanding reliability of boiler control systems. Factory testing of all the controls grants you the peace of mind that everything should work just as advertised. Cast Iron Swing-Open Burner Door Swing-open doors improve accessibility to the boiler.