Old non-TRV radiator valves

[u0362565]

Hi all,

I have old style radiators, on one side is a plastic cap with a circular arrow on top and a +- sign (lock shield valve?). I can turn the cap which presumably opens or closes the valve to allow how water into the radiator. However, is the valve simply open or closed or is it variable so that the flow of hot water into the radiator can be regulated? Because i can turn the plastic cap through several revolutions i'm assuming you can fine tune how quickly water flows into the radiator? Radiators nearer the boiler should have the valve more closed down and ones further away more open?

If i have the function of the above valve correct, is there a valve on the other side of the radiator? There is no cap or means to turn it unless i use a tool of some sort. Whats this valve called and what purpose does it serve? I'm assuming its on the return side, feeding cold water back to the boiler?

Thanks a lot

 

[Dotty]

The one you can open by hand is your control valve and is a crude method of controlling the temperature in the room by reducing the flow of water through the rad. The valve you need a tool for is the lockshield and is used to balance the heating system to ensure all radiators heat up at the same rate.

 

[u0362565]

Ok thanks, in that case are these old temp regulation valves a bit useless and should just leave them fully open?

What's the lock shield valve actually doing then, if its more closed this reduces the flow of colder water back to the main return pipe? If its open too much the refresh rate of hot water is too much? I may just leave them alone i assume they will have been balanced at some point in the past.. I live in a rented flat. Thanks again