The VMP (Vertical Multi-Port) is built for heavy-duty steam duty, with a pressure vessel 30% thicker than ASME requires and heavy-walled schedule 80 flue pipes.
Fulton lists fuel-to-steam efficiency up to 84%, steam quality above 99% and linkageless controls with turndown up to 8:1. The tubeless design has no tubes to replace and a compact vertical footprint.