Posted in Product Information

The water supply network must be protected from contamination should the characteristics (risk assessment) of the supplied water change.  Arrow Valves specialise in products that prevent this from occurring and many of our products have their humble beginnings because a specific installation required a bespoke product to serve this purpose.

Take a major hotel in London undertaking a full refurbishment, part of the brief was to install douche hoses for personal hygiene in the bathroom.  Douche hoses are a fluid category 5 risk and must be separated from the mains supply by a physical air gap (Type AA or AB).  The Water Regulations insist that each individual fitting is separated to prevent cross contamination; the term used is ‘Point of use Protection’.

To compound the problem the water supplied from a douche hose needs to be at a safe 37⁰- 41⁰C, the perfect breeding ground for bacteria.  With the water temperature and the requirement for point of use protection a must, a centralised plant was not an option and individual units would be needed.

Our solution needed to be a compact unit that housed all the components to aid installation, noise levels to be below 45db so that no sound would intrude into the room.  The simplest solution with respect to size was our trusted “Midi-Break” unit with an instantaneous heater, but a 12kw load across 152 units could have resulted in a huge demand for power, large cables to each unit and a delay in producing warm water.

The final solution was a compact unit housing an AB break tank, a pump, 10 litre hot water storage heater and a TMV3. Water was now stored above 65⁰C eliminating the risk of bacterial growth. The TMV3 would blend temperatures down to a safe level and fail to cold in the event of a problem – 25mm thick acoustic foam provided the attenuation required to reduce the DB rating of the unit and finally one 13amp supply, 2 water connections (in & out) and an overflow was all that was required to connect the unit up.

BTHW-1 is 1000 mm tall, 400 mm wide and 210 mm deep.  The hotel installed 152 units and the unit has continued to enjoy success as a standard product.  A new quick recovery 5 litre heater in stainless steel is now employed, solenoid fill and a fully detachable door to aid installation is now standard.