Hot Water Temperature Maintenance

nVent RAYCHEM hot water temperature maintenance systems offer comfort and an intelligent way to supply instant hot water at the tap.

Why install a hot water maintenance system? Hot-Water-Temperature-Maintenance

  • Long, complex pipe networks are energy inefficient
  • Waiting for water from the tap at the desired temperature level can waste lots of valuable drinking water
  • Legionella prevention and decontamination in long and ramified pipe systems are much harder to execute

These are typical issues in buildings including

  • hotels
  • healthcare buildings & hospitals
  • office buildings
  • sport buildings
  • schools
  • prisons
  • apartment blocks

The system consists of RAYCHEM self-regulating cables and the HWAT-ECO control unit:

  • Engineered for direct application on hot water pipes, the RAYCHEM system does not require return pipes, valves or pumps
  • Self-regulating heating cable is positioned on the pipe and compensating for any temperature loss in hot water and maintaining the desired temperature along the pipe
  • Parallel circuit construction of the heating cable allows design and installation flexibility
  • The control unit manages the power consumption of the system in an efficient way to get energy savings


Reasons to install a nVent RAYCHEM system

1. Single-pipe system for easy design and faster installation
RAYCHEM HWAT heating cable is simply fixed on the supply pipe - no need for return pipe work, valves or pumps, or for complex design and balancing work associated with return systems.

This results in :

  • Lower installation cost
  • Less pipe system maintenance work.
  • Flexible heating cable installation along the entire pipe network due to a smart Rayclic connection system

2. Up to 50% of energy savings vs traditional recirculation system
The HWAT-ECO control unit reduces the running cost of the hot water maintenance system. Traditional control equipment and timers can save up to 30% compared to an uncontrolled system. The implementation of a HWAT-ECO controlled system save up to 50% energy.

The HWAT-ECO is a smart control unit that limits the heat output of the self regulating heating cables according to the specific requirements of the hot water system. It combines the clock time functions with the boiler thermostat in order to ensure that the system is used solely for temperature maintenance. This avoids superfluous heat production and minimizing energy consumption.

3. A retrofit operation of an existing traced hot water system with HWAT-ECO control unit is results in a short investment payback period.

Energy consumption
See how much energy can be saved by using the appropriate control unit and how fast your investment pays back.

Energy Consumption Comparison

nVent RAYCHEM self-regulating systems offer the most flexible approach for heat-tracing design. Cable can be cut to length on site for the most complex installations. Typical applications are line lengths of up to 250 m and maintain temperatures of up to 150°C. The parallel cable construction allows for installations on branch offs if required.

System features include:

  • Selectable temperature levels: Maintain or Economy temperature
  • Thermal Legionella prevention programmes
  • BMS compatible
  • Control units can be put in a network for fast programming
  • Nine building-specific programs
  • Alarm relay for remote monitoring

Thermal legionella prevention

As a result of the hot water single-pipe system having fewer pipes, less water volume and less heat loss, the danger of any bacteriological problems is significantly reduced.

  • Shortest pipe network of all central hot water temperature maintenance system: (´half pipe length´, so no return pipes)
  • Guaranteed high temperature (>55°C) throughout the system, over its entire length and no unheated zones
  • Small mixing zone in the storage tank (no runback into the storage tank)
  • Temperature maintenance possible as far as the tapping point
  • Renewal of water in the pipe network: pipe volume is 100% renewed with each tapping

Decontamination is completed by increasing the temperature of the water. The use of the HWAT-R heating cable with the HWAT-ECO controller offers the benefit of selecting a desired temperature and increasing the temperature over a time for legionella prevention. As such, the HWAT-ECO controller can be programmed for a Legionella prevention cycle.

Download the legionella application document (pdf 107 KB)

nVent Thermal Management Installs Heating Solutions at London Rolex Building
Key Challenges

nVent Thermal Management was brought in to employ a variety of its heating solutions at the new Rolex Building in London, England. Rolex was looking to convert its heating to a simpler, lower cost single pipe system that required less maintenance.


nVent Thermal Management provided hot water services using the nVent RAYCHEM HWAT single pipe hot water temperature maintenance system.


nVent Thermal Management installed more than 400 meters of cable to provide hot water all the way to the point of use, 600 meters of WinterGard pipe frost protection cables, and RayClic connection devices to safeguard the chilled water supply lines from freezing.

In addition, a beautifully tiled floor at the entrance foyer now welcomes visitors with the ambient warmth of RAYCHEM floor heating systems, with the installation of nearly 50 square meters of T2QuickNet.


The reduction of pipework left more space for the single pipe and insulation so that thicker insulation over the system could be used to increase its efficiency. The total estimated energy savings for this project will be approximately 50-60 percent. Even with the higher unit cost of electricity, the actual customer savings are expected to be 5-15 percent.

The design, supply, and installation of the RAYCHEM systems were undertaken by Jointing Technologies, a nVent Thermal Management distributor partner headquartered in South East England. The project was completed in October 2010.

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