You owe it to yourself to warm up to our BIASI boiler systems. Our economical and highly efficient 3-pass design offers the flexibility of using either an oil or gas burner. Our unique GG20 cast-iron block, with its 58 PSI rating and easy-access swing door, is unsurpassed in durability and efficiency, providing years of trouble-free operation. There are 7 models ranging from 265 to 658 MBH, which are well-suited for commercial or multi-unit buildings. We have tested our systems extensively to Hydronics Institute Standards. BIASI’s foundry is ASME certified.


  • Outputs from 61,000 BTU to 256,000 BTU
  • Gas or oil burner compatible
  • Easy access swing door
  • No flue required; can be direct vented outdoors
  • Low water content boiler heats up faster with less fuel
  • Efficient 3-pass heat exchanger boiler design
  • GG20 cast-iron construction for superior heat retention and durability
  • ASME and ULC listed
  • 58 psi cast-iron construction


  • 20 Year Limited Warranty on the boiler block to the original purchaser


B-40 Literature



B-40 Manual