Unvented Hot Water Cylinders

Servicing Unvented Hot Water Storage Systems
Unvented storage cylinders are increasingly popular. Because they supply mains pressured water meaning you get a good shower and not a dribble as can happen with traditional non-pressurised cylinders. The main drawback is the inherent danger with large tanks of hot, pressurised water. There were accidents in the past which caused lots of damage and even loss of life!
It is essential that all unvented cylinders are installed and serviced by competent persons.
Risks associated with unvented systems
Unvented water heaters incorporate three levels of safety. Thermostats that prevent the water being heated above 60 – 65c, high level cut-outs that operate when water reaches 80 – 85? because the thermostat has failed and a temperature relief valve, which operates if both of the other safety features fail and the water reaches 90 – 95c. In addition unvented water systems also incorporate a pressure relief valve which operates at 6 – 7 bar.
If these safety features are missing or have become faulty then there is a risk that the water will overheat and pressure will build up in the water storage tank.
Unvented cylinders should been installed by approved installers, who will have notified the local authority of the installation.
When replacing parts on an unvented system it is important to always use replacement parts supplied by the manufacturer of the system.
For further indepth reading about unvented hot water cylinders and general information about water heating please try these links.
http://wiki.diyfaq.org.uk/index.php?title=Unvented_DHW

http://en.wikipedia.org/wiki/Water_heating

How will your unvented system be serviced?

  • The servicing of an unvented hot water storage system will include the following:
  • Inspecting for signs of wear or damage
  • Checking to see that the correct manufacturers parts are fitted
  • Testing the temperature and pressure relief valves
  • Removing the line strainer and cleaning the filter
  • Checking the pressure of the expansion vessel
  • Setting the correct incoming water pressure
  • Continuing maintenance

It is recommended that unvented water heaters are serviced once each year and that a record of this service is kept close to the water tank. If you would like your unvented cylinder serviced please contact us.

We work on the following water heater systems

  • Albion
  • Heatrae Sadia
  • Keston
  • Flamco Flexcon
  • Santon Premier
  • Vaillant uniSTOR
  • Heatline
  • Santon Premier Plus
  • OSO
  • Ariston
  • Telford
  • Fabdec
  • Heatrae Megaflo