The Instinct features an all stainless steel fire tube heat exchanger. Solo sizes come in 110, 155, 199 MBH and can be cascaded up to six boilers. Instinct Solo boilers can be paired with our Smart 316 indirect tank to provide an abundance of hot water. CTRLMAX Control System-EZ Setup allows for a quick :60 second setup. Easy troubleshooting in plain text, no codes. 3-in-1 Universal vent adapter directly accepts PVC, Polypropylene, and Stainless Steel.