heating and boiler problems – lovekin.net
Please read our Legal Disclaimer
Modern radiator valves are fitted to the bottom of the radiator; some older radiators have one valve fitted at the bottom and one at the top, usually on opposite ends. Certain new radiators have the valves fitted at the bottom of the radiator, midway along its length.
Normally the only difference between the wheelhead valve and the lockshield valve is the plastic cap; the wheelhead cap turns its valve whereas the lockshield cap locks its valve in a set position or spins freely without engaging the valve.
The wheelhead valve is normally used either fully open or fully closed, depending on whether you want the radiator on or off.
The lockshield valve is set to a certain position during radiator balancing and then remains fixed in this position. To set the valve you take off the plastic lockshield cap and then use either a spanner or the wheelhead cap (from the other valve) to turn the lockshield valve.
When you have the valve correctly set you refit the lockshield cap which prevents the valve setting from being altered.
Right angled (90°) wheelhead and lockshield radiator valves. The only difference between these two manual valves is the cap. The wheelhead cap turns the valve; the lockshield cap locks the valve and prevents it turning and altering the set position chosen
Straight (180°) wheelhead and lockshield radiator valves. Again, the only difference between these two manual valves is the cap.
Unfortunately most of the manual radiator valves around are cheap and nasty and, if used, prone to leaking.
Unless a valve had been badly fitted or damaged, the most likely cause of leakage is a leaking gland. The gland is the point at which the spindle of the valve passes into the valve body.
Manual radiator valve with the plastic cap removed. The first nut down the spindle (here coloured in red) is the gland nut
The packing in the gland is designed to prevent water leaking out around the spindle and is compressed around the spindle by the gland nut, shown coloured red in the photo above. Tightening this nut compresses the packing and may stop any leakage. If you tighten too far the spindle becomes too stiff to turn.
Some manual valves have gland nuts which are already tightened hard down and are sealed internally by an 'O' ring. These valves show no visible thread on the gland nut itself. Once the 'O' ring wears, the valve will leak. If this type of valve leaks, setting the valve either fully closed or fully open may, temporarily, control the leaking but the valve will need to be changed.
It may be possible to replace the 'O' ring in the gland but removing the gland nut completely is risky; on some valves the spindle may come right out together with loads of dirty water. Back to the top
This large wheelhead radiator valve is an old fashioned Peglers Belmont manual valve. Most radiator valves are ½"
This chunky ¾” valve was used on larger cast iron radiators.
We'll add information about radiator valves as soon as we can. We'll also be dealing with replacing radiator valves.
Thermostatic Radiator Valves — TRVs
A selection of Honeywell thermostatic radiator valves (TRVs)
Applying PTFE tape to the threaded tail of a lockshield manual radiator valve
The taped tail of the lockshield valve, ready to be fitted into the radiator
This article is copyright but you are welcome to link directly to it if you have your own site.
The hyperlink is http://www.lovekin.net/radiator-valves.html