Balancing central heating system when no lockshield valve

Hi,
I'd like to balance our central heating system as we can never get all the upstairs radiators to come on all at once, there's always one or two that are stone cold. I've read up on balancing the system and seen that I have to adjust the lockshield valves on each radiator. Now, here's the problem. The majority of our radiators do not appear to have such a valve. There are one or two, obviously more modern radiators in the system and, sure enough, they have a lockshield valve. The older radiators simply have an on/off knob and the bleed valve.
How would I go about balancing this sort of system or should I just bite the bullet and replace these older radiators with more modern, efficient ones?
Cheers,
Matt
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On 8 Dec 2003 13:18:16 -0800, snipped-for-privacy@hotmail.com (Matt) wrote:

Add lockshield valves to the older radiators??
.andy
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Yes, that's the answer - there's no point in replacing the rads as you will still need to add LSVs to the new ones (assuming the old ones are big enough).
Perhaps you didn't realise that LSVs are sold separately from rads.
Do check http://www.diyfaq.org.uk/plumbing/rad-balance.html as well as http://www.diyfaq.org.uk/plumbing/plumbingpage1.html#balancing
-- Phil Addison The uk.d-i-y FAQ is at http://www.diyfaq.org.uk / Remove NOSPAM from address to reply
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     snipped-for-privacy@hotmail.com (Matt) writes:

If they are on a single pipe circuit, there will probably be a single lockshield valve for the whole circuit, in which case it's that you would adjust. Do the cold ones come on if you turn off some (or even all) of the hot ones? If not, you probably have a different problem.
--
Andrew Gabriel

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Indeed, that's exactly what happens. I turned off two radiators last night and, sure enough, the two that were cold started heating up. So, the inevitable next question. Where would this single lockshield valve be located typically?
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"Matt" wrote | Indeed, that's exactly what happens. I turned off two radiators | last night and, sure enough, the two that were cold started heating | up. So, the inevitable next question. Where would this single | lockshield valve be located typically?
In the most inaccessible place possible :-(
Owain
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On Tue, 09 Dec 2003 00:42:20 +0000, Matt wrote:

At the other end of the radiator from the control valve. Typically on the return but not necessarily so.
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Ed Sirett - Property maintainer and registered gas fitter.
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