unvented hot water cylinder with double hotun hiflo installation

A great example of a compliant unvented hot water heater T&PRV and PRV discharge solution using two hotun hiflo units by Dean Torris

For large unvented water heaters (greater than 15 litres capacity), hotun hiflo dry trap tundish provides the perfect solution with a simple, compliant, single product T/PRV discharge installation.

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The revolutionary design has two industry standard connections, for a quick and easy installation saving you time and money.

Connect the water heater’s temperature/pressure relief valve (T/PRV) through hotun hiflo and then direct to a local waste or foul drain, without allowing odours to ventilate back into the building.

This provides an air break to drain with a safe and visible means of discharge, thereby allowing a single product compliant* connection.

The flow capacity of the hiflo unit is 18L/min. If your system T&PRV has the possibility of discharging volumes greater than this under failure operation, the installer must assess on a job by job basis that he/she is happy that the installation will operate safely under a failure on failure basis.

hotun hilfo – the tundish evolved

Product Features

  • 126mm tall x 57 mm wide
  • 1/2″ flat face tap connection on inlet
  • 32mm HDPE or universal/compression compatible outlet
  • Allows trickle** and full-bore discharges up to 18 l/m
  • Temperature rated up to 100ºC
  • Air break to drain
  • Safe and visible means of discharge
  • 10 year warranty (T&C’s apply)

Commonly called: odour seal tundish, dry trap tundish, trap tundish, tundish valve, overflow tundish trap, dry odour seal tundish, sprung valve tundish, non return tundish

hotun’s patented and simple, but visually appealing style, has many advantages over other more expensive and bulky options

  • To go to the alternative compliant options page, click here
  • To see all the regulations that need to be considered when making this type of connection, click here
  • To see some video clips of hotun discharge flow tests (trickle and full-bore), click here
  • To view the full operation, installation, service and warranty instructions, click here
  • For typical unvented installation types, click here
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* It is compliant (when fitted in accordance with the installation instructions) with all necessary Water and Building Industry regulations, (in force wef Mar 2014) provided that the waste and/or foul stack can be demonstrated to be able to withstand the effects of the expected temperatures being discharged. Please note, Polypropylene (PP) and High Density Polyethylene (HDPE) are generally accepted by building control to be used as suitable materials in this application. However, if in doubt, please contact your local building control for advice before installation.

** The spring/valve/diaphragm assembly is precisely engineered to hold the diaphragm shut under normal operating conditions (to prevent odours being ventilated back up from the foul waste pipes or drain), but still allow the valve to open with a minimal quantity of water in the upper chamber. We call this the trigger point and is set to release at between 5ml and 25ml of water. The upper chamber will hold 50ml of water before overflowing.

7 regulatory requirements – 1 simple solution