DIY Doctor UK DIY Forums

Hi,
We've ripped out the old back boiler and water cylinder and header tank and radiators, all that's left is the plumbing. We'll get an oftec engineer to install the new oil combi boiler, but I was going to fit the new radiators myself to save some money (done something similar once before).
I'm just a bit confused looking at all the TRV's and lockshields on offer in screwfix and toolstation - do I need a TRV on every radiator? What's the difference between a radiator valve and a lockshield? How do I choose which brand? Also I've got 10mm pipes, do any of these valves come in 10mm size or are they all 15mm with reducers?
Sometimes there's just too much choice.......

General advise is to fit all radiators with 1 TRV and 1 locksheild. The exception to this it one radiator (usually in a hallway) should have 2 lockshields fitted. This means that if someone shuts off all the radiators by using the TRV's and the heating still runs because its been left on a timer then the system should not have a problem.

The locksheild is there to allow you to balance the system so that all the radiators get equally hot.

A TRV differs from a normal radiator valve in that it will detect the heat of the room and once it gets to a certain level (depending on the level you have set the valve to) it will switch the radiator off. This means that you don't have all the rads running full bore because the one in the room where the thermostat is is turned off or down low.