I've a radiator with no caps on the valves, so how do I know which one is lockshield and which the wheelhead?

Answer 1

Turn on the heating and measure the temp of the both the pipes the hotter one is the wheelhead and the other is the lockshield.

Answer 2

Lockshield Valve Caps

Answer 3

Quite simple really. With the heating cold, start the boiler up and feel which pipe starts getting hot first, that will be the flow pipe. The other side would be the lockshield valve

Answer 4

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RE:
I've a radiator with no caps on the valves, so how do I know which one is lockshield and which the wheelhead?

Answer 5

excellent advice of which heats up first is the inlet and should be the wheelhead

the difference would be with a 'normal' system the temperature drop across the radiator and therefore heat distribution throughout the system is adjusted with the lockshield, the wheelhead is approx fully open. the lockshield would then be left alone, hence the name!

the answer of one being on the left or right is unfortunately cobblers, it depends on who fitted it

Answer 6

The wheelhead is on the feed side; the lockshield is on the return side. When the radiator is running, the feed pipe should be a couple of degrees hotter than the return pipe.

Answer 7

If this question is asked for the purpose of changing the valves, and you are fitting thermostatic valves, get the bi-directional valves and it will make no difference which side they are fitted, except to say, thermostatic valves work more reliably if fitted at the end which is in the most open space, ie not into a corner or behind furniture.

Answer 8

is it just me but why would you be surprised the system is either under higher pressure (combi) or lower pressure (vented) so of course water will come out when you open it up you can freeze the pipe once the system is off to avoid draining or drain to below the level of the valve in question, trial and error or for vented system bung up the two pipes in the loft feed and expansion cistern, some water will come out at first then stop for the befuddled call a plumber it stays hot for some time, would you expect a bath tub of water to suddenly cool, no

Answer 9

In practise the wheel head valve is on the left hand side of the radiator. But to be sure, next time you turn the heating on from cold, the wheel head valve will be on the side of the radiator which heats up first. Although either valve will stop water flowing through the radiator.
Good luck,
Rupert.

Answer 10

Actually there is very little difference. They are exactly the same valve but have different caps. If you get them wrong it will make no differnce to the circuit. The wheelhead cap will fit either valve.