In an earlier contribution to this discussion,
anon wrote:

From earlier posts on this topic it appears that a 'LockShield 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 35mm for a RV.


I think you're getting a bit confused with terminology!

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