Patented Pioneering Products

Save up to 3 hours of installation time on a boiler mounted on an internal wall by using hotun!

Professional plumber, heating, ventilation and air conditioning design engineer, Russell Armstrong (Mciphe), MD of RA Tech UK Ltd, the manufacturers of hotun products, invented the hotun range of dry trap tundishes and the worlds first in-tundish PRV water alarm unit (hotun detect), Russell says:

“hotun is unique, it is the only dry trap tundish on the market that has visible water at the point of diagnosis, and with our latest innovation, hotun detect, takes that concept to a newer, higher level!

”I am really proud of what we have achieved, designing, developing, introducing and bringing the products to the UK plumbing market”


picture of hotun tundish and hotun detect with worlds first branding wording
picture of hotun tundish and hotun detect with worlds first branding wording

New products!

Check out all the details and information you need to know. Plus, all of these new products will be on our stand at Installer24.

Tens of thousands of installers and professionals are now fitting the revolutionary and pioneering range of hotun dry trap tundishes, enabling the installers, to run a system temperature and/or pressure relief discharge pipe to an internal waste or soil pipe compliantly in a one-product solution, saving the installer many headaches, time and money.

We call this “The hotun revolution”

The original and pioneering hotun dry trap tundish was invented by Russell Armstrong back in 2013, and has fast become the industry’s go-to option for a relief valve discharge to an internal drain or soil pipe!


hotun 100 range

The original and ONLY dry-trap tundish on the market provides TWO vital advantages


  • Compliant at point of installation

  • Easy visibility at point of diagnosis

Key product features
  • Award-winning, visible/conspicuous & safe means of relief valve discharge from a sealed system boiler or unvented cylinder to an internal foul drain
  • Specifically designed to be Water and Building Regulations compliant, to allow either drips or high volume flow from the relief valve through the tundish without allowing foul odours or gasses back into the building
  • hotun is WRAS approved – air break to drain
  • Allows for easy identification of historical relief valve operation via its open-sided construction, residual water forms a small puddle on the top of the valve, making for a unique, industry-leading, easy, and effective diagnosis of discharged relief valve water
  • A cost-effective and simple solution
  • Quick and easy to fit
  • Easy maintenance and diagnosis from inside the building near the appliance, potentially saving the installer the risk of working at height either at time of installation or at point of diagnosis.
  • Accepted for use by many of the UK’s largest boiler manufactures
  • The hotun range is a tried and trusted product and is currently installed in well over a hundred thousand applications
  • Rated at 120 Deg C
  • For additional safety, we provide a separate finger guard (hotun shield) to prevent access to potentially scalding water for boiler applications, whilst still allowing easy visibility of discharged PRV water.

hotun SF range

Maintaining our industry-beating design benefits of;


  • Compliant at point of installation

  • Easy visibility at point of diagnosis

Key product features

The SF range gives you all the brilliant benefits of the 100 range above but with the following different key features:


  • Comes with an in-built push-fit inlet connector
  • Extended size range with a 22mm inlet connector
  • As with hotun 100, the SF range is fully WRAS approved
  • The entire SF range is fully Kiwa flow tested

hotun detect

Audible & Visual Alarm System for hotun Tundish

The hotun detect from RA Tech has been specifically designed alongside their innovative hotun tundish range to give an immediate audible and visual alert if there is something wrong with the heating or hot water heater system causing an overpressure (or temperature) and the relief valve to start to discharge water.

The consumer can then seek help to identify the fault with the system and then make effective and timely repairs saving water and energy and making sure that their heating or hot water system is functioning safely and satisfactorily.


Key product features
  • The world’s first, In-tundish water detection and temperature sensing audio and visual alarm system
  • Alarm unit provides an audible and visual alarm as soon as any PRV water drips into the tundish
  • Auto mute and auto re-set operation with manual override
  • Specifically meets G3 guidance (to aid people with impaired vision or mobility to let them know when something is wrong with the system)
  • Saves water and energy 
  • Suitable for any system where an active warning may be useful
  • Helps installers to advertise the importance of regular maintenance to consumers
  • Senses presence of water & temperature in 4 stages depending on temperature
  • Battery operated (2032 coin cell, supplied) with auto low battery power audible warning
  • Requires no specialist electrical knowledge to fit
  • Inbuilt, one press, manual battery condition check operation
  • Simple, quick, hook-on design, fitted in seconds
  • Compact size yet effective operation
  • Cost-effective and simple to use
  • Compatible with ALL hotun dry trap tundishes
picture of hotun tundish and hotun detect with worlds first branding wording

The Award winning hotun detect

(and critically acclaimed!)

hotun detect is the HVR News Awards Ancillary Product of the Year 2020.

We are pleased to announce that we have won the HVR Awards 2020 Ancillary Product of the Year!

Thank you to our team and all those installers who choose to buy and use our products.

RA Tech UK Ltd would like to thank all the event organizers and sponsors and above all wish to dedicate this award to Tim Lomax and in the Memory of Nick Shephard

Our hotun dry trap tundish is accepted for use by many of the UK’s largest manufacturers


Here is what they have to say:

Worcester Bosch Group

“hotun is a good solution to the issue of terminating PRV discharge pipes from a sealed heating system into a waste water system providing that the waste pipes are of a standard to accept the expected temperatures and pressures of the discharging water”
Martyn Bridges, Technical Director
(WB technical website)


The hotun addresses the issue of removing outflow from a sealed system pressure relief valve into an internal waste or soil pipe, preventing foul odours back into the building when connected to discharge pipes specified as suitable for the temperatures and pressures involved in the system
Martin Butcher, Technologies Specification Manager

(Vaillant website)


hotun provides a great option if you are not able to terminate your PRV discharge pipe to a safe location outside… The hotun has been used many times with our Small Electric Water Heater products including the Europrisma and most recently our Andris Lux models
Antonio Plana, Product Manager – Water Heating
(Ariston website)


The hotun hiflo is acceptable for use with ideal condensing boilers, it offers a useful solution to the issue of combining a sealed system boiler pressure relief discharge and condensate pipe into a single termination point to a buildings waste water system. Please note that the waste pipes need to be of a standard to accept the potential pressures and or temperatures involved with a sealed system under discharge scenarios

Andrew Dabin

Domestic Product Manager

(Ideal Boilers website (installers))



hotun and hotun hiflo are patented, dry trap tundishes and are the only dry trap tundish officially accepted for use by all of the following companies;


RA Tech UK Ltd are products are tested by accredited UKAS bodies

Read Our independent test reports for hotun dry trap tundishes UKAS Accredited

We are proud to be associates and members of many Professional Industry bodies

Product Registration

Click the button to register your hotun product. You must do this in order to be eligible for the Warranty.

Endorsements and accreditations

A list of endorsements and accreditations



Please click the button below for the hotun YouTube feed


Please click here for the gallery of hotun & hotun hiflo installations sent in to us by our customers

Trade Suppliers

A list of our trade suppliers and stockists and suppliers

Contact Us

T: 01332 702678