TM300 Thermostatic Mixing Valve

The Honeywell TM300 Thermostatic Mixing Valve (TMV) is approved to the requirements of the Buildcert TMV2 scheme, providing safety shut off control of water temperature for hot water supply systems. Other versions of the TM300 are available for non - TMV2 mixing applications such as underfloor manifold and radiator heating control. The TM300 is a requirement for installation into hot water outlets in schools and social housing for the elderly. It is recommended for use in all other properties to protect against the danger of scalding from baths, wash basins and sinks. The TM300 can be fitted to a single outlet or to several outlets, provided that both water supply pressures and flow rates are adequate. The valve is WRAS and Buildcert approved.

The BuildCert TMV scheme recommends the following maximum hot water temperatures for use in all premises: 46°C for bath fill; 41°C for showers and washbasins; and 38°C for bidets. However, while 46°C is the maximum temperature for water from the bath hot tap, it takes into account the temperature loss in metal baths, especially in cold bathrooms. It is not a safe bathing temperature for adults or children. The British Burns Association recommends 37 to 37.5°C as a comfortable bathing temperature for children. In premises covered by the Care Standards Act 2000, the maximum water outlet temperature is 43°C.

For more advice on regulating maximum hot water temperatures, see Building Research Establishment (BRE) Building Bulletin IP 14/03 and The School Premises Regulations/National Minimum Care Standards Section 25.8.


  • Fast, sensitive integral sensor
  • Non return valve in each inlet
  • DZR brass & chrome plated body
  • Locking cap prevents accidental adjustment
  • Can be installed in any orientation
  • Flange connection means easy removal without disturbing pipework
  • High flow rate at low head



  • 22mm TMV2 approved mixing valve
  • 22mm & 28mm mixing valves