All unvented water heaters and cylinders have a failsafe valve, known as a pressure relief valve, to protect the tank from excessive pressure build up during the water heating process. This valve needs to be able to expel water or steam via a pipe attached to the valve, and ideally this needs to be through an outside wall to a drain, via a tundish. (What is a tundish? It is a device placed close to the pressure release/relief valve that allows people to see if water has escaped the system due to excessive water pressure)

The reason you wouldn’t have this arrangement inside a property would be the issue of drain smell through the tundish. Until recently, that is.

There is now a way of connecting this pressure relief valve to an internal waste pipe, thanks to a fairly new product: the Hotun.

The Hotun is a ‘dry-trap tundish’ that incorporates a non-return mechanical sealing diaphragm, making it safe (and satisfying the relevant regulations) to use to connect to internal waste systems.

What is a tundish? A tundish is a device placed close to the pressure release/relief valve that allows people to see if water has escaped the system due to excessive water pressure.

There are a number of different sizes and types to suit all applications from a small undersink water heater right up to a large commercial cylinder, and also central heating boilers. Pretty much all models are available in either black or white. There are a few accessories available for them too, including a shield and even an automatic alert system!

So the benefits of the Hotun include:

  • Small-sized and ideal for use in small spaces
  • Users are able to visibly see the PVR discharge.
  • Ability to deal with trickle and full flow discharge conditions
  • Hotun & Hotun SF 15 – 22 has a flow capacity of up to 16 litres/minute
  • Hotun hiflo & Hotun hiflo SF 15 – 32 has a flow capacity of up to 25 litres/minute
  • The current largest unit, Hotun XLSF 22 – 32 has a flow capacity of 40Litres/minute
  • Compatible with any unvented hot water heater or sealed system boiler PRV discharge pipe
  • Removes the risk of wholesome water supply contamination
  • Eliminates the need for any drilling work through external walls
  • Standard plumbing connections are used on the inlet and outlet

To summarize, in one simple fitting, the Hotun dry trap tundish solves the problem of compliantly running a Pressure Relief Valve (PRV) discharge from a pressurized hot water cylinder relief valve or boiler pressure relief valve to a local waste or soil pipe.

If you’d like further help or advice regarding the Hotun Tundish range, please call one of our Electrical Deals Direct water heating nerds on 01934 253600, drop us a line at sales@electricaldealsdirect.co.uk or use our friendly online chat on the website.