1998 Raypak Raytherm Indoor Hydronic Boiler – 66 HP. Model: H1-0962 S/N: 9807151099. Natural Gas. Input BTUH: 962,700. Output BTUH: 788,600. H1: mechanical modulation, set point 150F-210ºF. The Raytherm type H models have a 82% efficiency which, according to Raypak, is the highest of any atmospheric boiler. Max operating temp: 230ºF. Gas port: 1 in. Water ports: 2.5 in. Flue diameter: 14 in. Approximate shipping weight: 705 lbs. Removed in running condition late 2013. Overall dimensions: 32.5 in. W x 52.375 in. L x 33.5 in. H.