Peerless Boiler are our go to for vertical pass cast iron boilers. Peerless has an impeccable reputation for strength and reliability. The lifetime warranty that Peerless offers is proof of confidence in their product. Greenseal has a 25-year history of success with Peerless boiler installations. With thousands of installations our data speaks for itself. This is why we stick with the number one selling boiler for over two decades.