The heart of the Hubbell Instantaneous Steam fired water heater is a compact, highly efficient, and versatile spiral tube heating coil which offers many advantages over a conventional "U" tube design including:

• 100% counterflow for heat-transfer rates up to 40% greater than equivalent straight tube exchangers.
• Pressure drop is minimized.
• Bourdon tube configuration that allows entire assembly to expand and contract without localized stresses. Failure from thermal shock or mechanical process is rare.
• No baffles.
• ASME Section VIII Div. 1 Certification standard.
• Variety of materials available to suit specific applications.
• Compact design for easy maintenance.
• Parts in stock to prevent long and expensive down times.