Variable Fire (VF) Circulating Water Heaters VWH

Up to 87% efficient, hot water supply with modulating fire 4:1 turndown.


  • Venturi-mixing gas/air ratio system works with variable speed blower to precisely mix gas and air throughout firing range
  • 4:1 turndown fully modulating capability prevents energy stealing short cycling and provides smooth system operation with higher overall system efficiencies
  • Advanced electronic control changes temperature, operates the pump and provides a large amount of operational data
  • Compact, low-profile design which is ideal for boiler rooms with limited access
  • Factory start-up included
  • 5 year limited tank warranty and 1 year limited parts warranty