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Lockshield vs Radiator Valve



or a 'Radiator Valve' can be used to balance DCH flow.

Apart from about 4 quid, the obvious difference to me is that the
radiator connection on the LSV is external by means of spanner, and the
RV is internal by allen key and the LSV appears to have a crush type
copper washer to seal the valve instead of a spherical seating.

One benefit of the LSV is that it's possible to use 2 opposing spanners
to prevent the threaded radiator insert from rotating when tightening
the valve - whereas with a RV there's a risk of the insert moving and
accidentally bending the 15mm copper pipe.

I've pretty much answered my own query but would appreciate any
comments, particularly on the copper crush washer - i.e. are they one
shot items that are replaced if the rad is removed?

If anyone is thinking of replacing please note that the centres appear
to be the same as TRV at about 45mm from the end of the rad, instead of
I think you're getting a bit confused with terminology!
Yes, I'd go along with that Roger! A closer look at my new TRV's (same
'tail' as the LSV's at Screwfix) have olive compression joints - not a
flat washer as I first thought.


A manual radiator valve and a lockshield valve are excatly the same animal -
the only difference being that a RV has a knob to enable the shaft to be
rotated whereas a lockshield has a non-rotating cover - which is fitted
after adjusting the valve with a small spanner. Many valves are supplied
with both types of head/cover, so that you can use them for either
application.

All valves come in two main parts - the tail which screws into the radiator,
and the working part of the valve itself. Tails have either an internal
hexagon, allowing them to be screwd in using an Allen key, or an external
hex or square allowing them to be screwed in using an open-ended spanner.

The two parts fit together using either a conventional compression fitting
with olive and nut (in which case the tail has a plain end) or using conical
mating surfaces and a back-nut. The sort which use compression fittings can
I was refering to the tail which has a spherical / radius / torus
seating (to fit the valve cone)

It's worth pointing out LSV's extend a further 10mm so anyone replacing
a RV for a LSV needs to be able to move the pipe or elongate the hole
in the floorboard.
Err, this depends on the valves used. some makes models will be the
same, some different.
I said no such thing - it was written by 'anon'. Please be careful when
trimming to make sure that you quote the right source!


I'm converting a single pipe system to twin pipe and replacing the
radiators for convector type. The old RV's were perfectly servicable so
I've used the best one for upstairs and will probably go for LSV's for
downstairs as they look neat and may have the edge on RV's for
tightening and watertightness.

Many thanks for your comments Roger

be fitted either way round - with the shaft either vertical or horizontal.
Many TRVs are made this way.

35mm for a RV.