Hot Water Temperature Maintenance

Large commercial buildings need a way to provide hot water at the tap in the most energy efficient way, without long waits or wasting water. Hot-Water-Temperature-Maintenance

Hot Water Temperature Maintenance Heat Trace System

nVent Thermal Management has a sophisticated domestic hot water temperature maintenance (HWAT) system that provides immediate hot water at the tap that is more energy efficient and saves more water than a recirculation system.

Whereas, a recirculation system:

  • Requires that you keep the water heater temperature in the system at least five degrees above the maintain temperature to compensate for the heat that is lost in the recirculation loop.
  • Requires return lines, pumps, and balancing valves as part of the system.

nVent Thermal Management hot water temperature maintenance (HWAT) system provides a simple, reliable alternative to recirculation in commercial buildings. The HWAT system:

  • Maintains the water at a uniform temperature along the entire length of the supply pipe.  Thus, it is unnecessary to heat the water above the maintain temperature.
  • Includes HWAT heat trace cables that can be installed up to the fixture, which mean that you get hot water faster and waste less water.

HWAT is a fully integrated system that includes:

  • Electric heat trace cables – the HWAT-Y2 and HWAT-R2 heat trace cables adjust their power output along the entire length of the pipe to compensate for variations in water temperature and ambient temperature. These cables are designed for installation on hot water supply pipes underneath standard pipe insulation.
  • Connection kits and accessories – items for making electrical connections and properly completing the installation, such as power connection and end seal kits.
  • Advanced control systems – electronic controllers that monitor and/or control the desired temperature maintenance of the pipes.
The HWAT-ECO and ACCS-30 electronic temperature controllers optimize the energy efficiency of the HWAT system by controlling the pipe temperature with either HWAT heat trace cable.  The temperature set point can be programmed on a 24/7 schedule to suit the specific job requirements, providing the maximum water temperature control and energy savings to the end user.
Self-Regulating Technology

nVent RAYCHEM HWAT self-regulating electric heat trace cables automatically adjust their power output to compensate for temperature changes. Heat is generated as electric current passes through the conductive polymer core between the conductors. As the temperature drops, the number of electrical paths through the core increases and more heat is produced. Conversely, as the temperature rises, the core has fewer electrical paths and less heat is produced.

RAYCHEM HWAT self-regulating heat trace cables:

Self regulating

  • Have a cross-linked, conductive polymer core forming a parallel circuit
  • Have a self-regulating core that limits the maximum temperature that the heat trace cables will maintain, making them compatible with both metal and plastic hot water distribution pipes
  • Offer HWAT-Y2 for 105°F to 125°F and HWAT-R2 for 105°F to 140°F maximum maintain temperature
  • Are protected by a tinned-copper braid encased in a durable outer jacket to withstand mechanical abuse during installation
  • Feature an aluminum barrier to protect the heating cable from plasticizers which diffuse from commonly used closed cell foam insulation

Advanced Control Systems

The HWAT system includes two different electronic controllers, the RAYCHEM HWAT-ECO and the RAYCHEM ACCS-30.


RAYCHEM HWAT-ECO and RAYCHEM ACCS-30 controllers:
  • Provide 24/7 programmable pipe temperature set points, to allow for maximum energy efficiency and the greatest user flexibility. Temperature set points include:
    • Maintain :  The setting that lets you set the hot water delivery temperature set point.
    • Economy :  An energy savings feature that lets you lower the temperature set point when hot water is in low demand.
    • Off :  The setting that lets you turn the heating cable off when hot water is not needed, or after a heat cycle when the pipe needs to cool.
    • Heat cycle : The setting that lets you raise the temperature above the hot water delivery set point whenever you wish to sanitize to the water in the pipe.
  • Do not require pipe temperature sensors for water temperature control, instead, the controllers provide on/off duty cycle control to the heating cables to only provide the power necessary to keep the pipes at the desired set points, saving energy and providing temperature flexibility.
  • Provide water temperature monitoring, alarm and Building Management System (BMS) integration.

In addition, the HWAT-ECO:

  • Is ideal for smaller buildings with limited hot water distribution systems
  • Can control a single heating cable circuit

In addition, RAYCHEM ACCC-30:

  • Is ideal for large hot water distribution systems or multiple heat-tracing applications
  • Can control up to 260 heating cable circuits

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