The ‘RadPlan’ VTL120 is a matching TRV and lockshield valve set. The TRV regulates heat output and the lockshield valve limits water flow through individual radiators in wet central heating systems. According to Building Regulations Part L1 TRV’s should be fitted “on all radiators except in rooms with a room thermostat” to satisfy either Minimum or Best Practice installations. The valve can be mounted vertically or horizontally at either end of a radiator. To work correctly, the VTL120 pack should be installed on radiators in two pipe heating systems and also have a free flow of air around the TRV head to sense temperature.