The DW (double wall) version of the Armstrong Flo-Rite-Temp Instantaneous Water Heater uses a double wall tube to provide positive separation of the steam and water in the heat exchanger. The area between the walls of the tubes vents to atmosphere so you can detect tube failure without cross-contaminating either the steam or water. The Flo-Rite-Temp DW is well suited for all hot water applications where steam is available and plumbing codes or safety requirements prevent the heating medium and the portable water supply from being cross-contaminated.
The Flo-Rite-Temp DW Instantaneous Steam/Water Heater has a unique feed forward design which features a differential pressure diaphragm actuated mixing unit integral to a shell and tube heat exchanger.
The Flo-Rite-Temp DW mixing unit manages the water flow through the heat exchanger based upon downstream hot water demand and eliminates the requirement for a modulating steam control valve.
Speed of Response
The differential pressure diaphragm within the mixing unit rapidly responds to a change in system demand and significantly reduces the lag times typically associated with feed back/modulating steam control valve systems.
The Flo-Rite-Temp DW mixing units diaphragm actuated design can be described as "failure safe" because in the event of a diaphragm failure the mixing unit will fail with a cold bias and will not allow hot water to exit the heat exchanger.
Temperature Control and User Safety
Capable of controlling outlet temperatures +/-4°F, this principal of operation offers the additional relevant benefit of reducing the waterborne bacterial content of the water during the overheating process. In addition, with no water storage requirement, Flo-Rite-Temp DW water heaters are a sensible selection as a component of a broader system design initiative for Legionella risk reduction.
Ease of Maintenance
Accessible "non helical" admiralty brass straight tubes inside the carbon steel shell available mechanical cleaning and visual inspection. Non modulating constant steam pressure ensures condensate drainage and removes the potential for water hammer damage and corrosion. There is no steam control valve to maintain and typically no supplemental condensate return equipment required.
Ease of Installation
No storage tank, small footprint, access via a standard doorway and pre-piped packaged solutions reduce installation time, space and expenditure.