Technical - Artius PP

Technical Information Regarding TMV and RPZ Valves.

Artius PP are specialists in both Reduced Pressure Zone valves (RPZ valves), and Thermostatic Mixing Valves (TMV). Trained to install, fix problems and ensure that technical product knowledge is always to a high standard.

Reduced Pressure Zone valves (RPZ valves)

The Reduced Pressure Zone Assembly (RPZ) will prevent back siphonage within a water supply network. The principle operation of an RPZ valve is very simple. The valve consists of three sections :- Down Stream Check Valve, Discharge Chamber and Upstream Check Valve.

In the event of a problem, system and negative pressures are created causing back siphonage, the RPZ valve will prevent the contamination of the water supplies on the inlet side of the valve. The valve will automatically close the inlet supply and the discharge valve will open and discharge water to drain until such time as the pressure returns to normal. At this point the discharge valve will close, the inlet check valve will open thus restoring the water supply to the system. For many years, the installation of an RPZ valve has been common practice throughout Europe and the USA. When the Water Byelaws Scheme was replaced with the Water Supply (Water Fittings) Regulations 1999, the benefits and advantages of an RPZ valve were recognised.


In the majority of areas,throughout the UK, we draw drinking water directly from the mains supply pipe. It is therefore essential that the water within the distribution networks is free from contamination. The installation of an RPZ valve in certain circumstances has been recognised as offering the same level of protection to the water supply mains as a type A air gap, which would normally be achieved via a ball valve and break tank/storage cistern. An RPZ valve assembly can be used to provide whole site, partial site or point of use protection against back siphonage.

Features of an RPZ Valve
  • WRc Approved
  • Compact Design
  • Robust Construction
  • Effective Protection
  • Reliable Product
  • Cost Saving
  • Anti-pollution
  • Effective Operation

Thermostatic Mixing Valves (TMV)

A thermostatic mixing valve (TMV) is a valve that blends hot water with cold water to ensure constant, safe shower and bath outlet temperatures, preventing scalding.

The storage of water at high temperature removes one possible breeding ground for Legionella; the use of a thermostat, rather than a static mixing valve, provides increased safety against scalding, and increased user comfort, because the hot-water temperature remains constant.