Lockshield valve

16 Apr 2006
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United Kingdom
I've recently stripped out the radiator in my bathroom and replaced it with a towel radiator but the towel radiator is very hot. I know you are supposed to balance a radiator but i don't have the clip on thermometers to do this. Can i just turn the lockshield valve in a clockwise direction( thereby closing the valve and resticting the flow), will this lower the temperature of the towel radiator?


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what are the other rads doing?

are they hot or cold

if hot then you are not going to achieve much in restricting the flow i would have thought.

also rads do get veryhot unless they are the low temp ones designed for schools hospitals etc...
Since it's summer, the probability is that the towel rail is plumbed as a bypass (heats whenever boiler / pump run) or on the same loop as the HW cylinder.

If it IS used as a bypass, it would be a Very Bad Idea to put a thermostatic rad valve on it without making other bypass arrangements. Otherwise, fit a TRV.
The radiator that was in the bathroom had a trv fitted. All i did was remove this radiator and fit a nice shiny chrome one in its place. Sorry i forgot to mention i have a combination boiler so my system is sealed. What do you mean by bypass and because its summer?

thanks for your inout


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Depending on which boiler you have, it may need a bypass (path from Flow to Return that is always open). Check in the boiler installation instructions.

Because you never said 'Combi', I assumed the HTR was on all the time, even with the CH off. If it's on a combi, it must be connected along with the other rads.

If the boiler needs a bypass and there is one, there's nothing to stop you putting a TRV on the HTR. Closing the lockshield valve will reduce the temperature of the HTR- but possibly the temperature setting on the boiler might be too high anyway. Especially with a combi, running your boiler at max wastes energy.
About a month ago when i was rewiring the house i found a valve that was connected between the flow and return of the 22mm heating pipes. I was curious to know what this was so you have answered that question as well, a bypass valve. What is the function of this valve?
As i said the htr is very hot, so i will close the lockshield valve and see what results i get from this.
The boiler is indeed set at maximum, i could turn it down a bit.
thanks very much for your help and advice, much appreciated

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