- Thread starter wristpin
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rtbcomp
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It's so you get the correct flow through all the radiators. The rads nearest the pump will get most of the water flow so the ones furthest away could run cool, larger radiators need more flow than smaller ones.
There should be two valves on each rad, one is used to regulate the flow, either manually and/or thermostatically operated, the other is called a lockshield. Adjust the lockshields to set the required flow through each rad.
EDIT - Kayos beat me to it!
There should be two valves on each rad, one is used to regulate the flow, either manually and/or thermostatically operated, the other is called a lockshield. Adjust the lockshields to set the required flow through each rad.
EDIT - Kayos beat me to it!
CRB
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It is making sure that the radiators all heat up before the control one switches the thermostat off. Flow through the control is limited, the next radiators are allowed a little more and so on until the ones furthest away are allowed full bore. The temperature between the inlet and outlet is meant to be 5degrees, I think.
At least that is what I, sort of, remember when I did mine.
Edit: Kayos and RTBComp beat me to it.
At least that is what I, sort of, remember when I did mine.
Edit: Kayos and RTBComp beat me to it.
Kayos
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Depending on what text you read (or how old you are) it should be 11 degrees between flow and return on an older boiler, and 20 on a condensing, however like most things in life it's better to do it by feel, and not the numbers.
It's rare for me to be first, but ch is kind of my specialist subject so it would be rude not to
It's rare for me to be first, but ch is kind of my specialist subject so it would be rude not to
brightspark
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do u want the bad news
if u start altering the valves and they havent been touched for years the stuffing glands will leak like hell and they normaly wont nip up 
if u start altering the valves and they havent been touched for years the stuffing glands will leak like hell and they normaly wont nip up 
waddycall
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In that case shut both valves undo the gland nuts and put a few wraps of PTFE in there.do u want the bad news
wristpin
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Thanks for all the info. Reason for the question was that since having a new boiler (oil fired) and the system power flushed I had one rad that was far too hot even with the thermostatic valve shut right down. Acting on your info found that the lock valve was wide open!
AndyStobbs
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They must have forgotten to reset it, after opening it fully to facilitate the flush
normspanners
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I went to a customers/friends house and they asked my opinion on their central heating.
the daughter had moved in with her daughter and they had converted the double garage of the bungalow into an extension /part of the new house which saw the house go from 4 beds to 6 the last room being the new lounge.
They ended up with a sort of court yd in the middle with a walk through to the garden which meant the last rad was only a few feet from the boiler but the other side of the walkway, meaning the water had to go all the way round the external walls of the house to get to the last rad.
There were only two of the rads in the new house actually get warm.
They had had quotes from 3 plumbers who said oh it was not designed correctly will have to change pipe from 22-28 and 15 -22 extra pumps BLAH BLAH BLAH £2500 ish and they might need a new boiler on top but would only know when the pipework was done.
I asked about had they tried to balance the system at all. oh no, they said there was no point as it was all wrong.
I said lets have a quick look wheres the thermostat, in the lounge, massive k2 with the main room stat in the corner,the lockshield wound wide open!!!.
well there you go fault one, set the room stat to max, knocked the boiler temp (was on max, fault two) down a little, so I had a quick scoot round 1/2 hr shutting the lockshields with nearly all in the main house on max.
and got all hot but the last rad just warm.
I said thats all I can do now need my temp probe but will come back.
went back few days later fine tuned it and it is still working fine now 3yrs later.
Also using less fuel oil than ever before.??
The boiler was cycling far too often, is my answer to it.
They were more than happy
the daughter had moved in with her daughter and they had converted the double garage of the bungalow into an extension /part of the new house which saw the house go from 4 beds to 6 the last room being the new lounge.
They ended up with a sort of court yd in the middle with a walk through to the garden which meant the last rad was only a few feet from the boiler but the other side of the walkway, meaning the water had to go all the way round the external walls of the house to get to the last rad.
There were only two of the rads in the new house actually get warm.
They had had quotes from 3 plumbers who said oh it was not designed correctly will have to change pipe from 22-28 and 15 -22 extra pumps BLAH BLAH BLAH £2500 ish and they might need a new boiler on top but would only know when the pipework was done.
I asked about had they tried to balance the system at all. oh no, they said there was no point as it was all wrong.
I said lets have a quick look wheres the thermostat, in the lounge, massive k2 with the main room stat in the corner,the lockshield wound wide open!!!.
well there you go fault one, set the room stat to max, knocked the boiler temp (was on max, fault two) down a little, so I had a quick scoot round 1/2 hr shutting the lockshields with nearly all in the main house on max.
and got all hot but the last rad just warm.
I said thats all I can do now need my temp probe but will come back.
went back few days later fine tuned it and it is still working fine now 3yrs later.
Also using less fuel oil than ever before.??
The boiler was cycling far too often, is my answer to it.
They were more than happy
