1. Will it be sufficient just to turn the thermostatic valve down to 'nil' to stop the flow of water on that side. 2. On the other side, there's a knob that looks as though it might control a valve. Does it? Will it be sufficient just to turn that valve on the non-thermostat side? It's been there for many years (hence my desire to replace the old rad.), so I dare say that it might not turn off very easily. 3. Would a prudent person have standing by a pipe freezer and a plug? (By plug I mean something to screw onto the threads of the open pipe.)
1. In theory, yes. See answer to 3.
2. Again, yes. Remove the plastic cover if there is one and get your wrecking clamps (aka mole grips) or if you're flash enough, the correct key and turn it off with this. The plastic cap is likely to be brittle and the valve stiff after all this time so you really do need to remove the plastic cap. See answer 3.
3. Yes. And some PTFE tape.
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Mapmaker
1. Yes, but beware if the nighttime temperature drops the valve might open (not usually a problem in summer but if you delay to the autumn or winter?). Better to fit the installation or decorating cap that is usually supplied with the TRV.
2. This is the lockshield valve, used to balance the radiator flow or to isolate it from this side. Remove the plastic cover (usually by hand is ok) and use a small shifting spanner on the central spigot to turn it off (screw it in as far as it will go).
3. Since this is a combi then the radiator primary circuit will be pressurized. When you slacken off the radiator tail pieces to drain the radiator itself (after 1 2) have some cat litter trays or similar to catch the water (these are good as they fit under the radiator).
Once the radiator is empty, disconnect the tails completely and lift the radiator off its brackets. Depending on its size you may need two people.
WARNING when tipping the radiator some black sludge may drip out, this contains iron and will indelibly stain carpet and flooring.
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I just hit post rather than preview.....that WARNING should have been in bold.
StarGazer
No sooner said than done. ND
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Thanks, ND & Stargazer. That red is a bit flash!
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I have done this a lot recently for a client.
I found the best way was to:
1. shut off both valves completely. If it is controlled by a Thermostatic radiator valve, then make sure that this is actually shutting the valve off. You can check this by removing the TRV control head then checking that the spigot underneath move freely.
COUNT HOW MANY TURNS YOU NEED TO SHUT OFF THE LOCKSHIELD VALVE. This valve is used to balance the heating system and if this radiator draws too much water then the rest of the system may suffer.
Once you are sure that both valves are completely shut off, then place a cat litter tray (remove cat first) or washing up bowl plus plenty of plastic sheet under the lock shield valve (the one that is not a TRV). Then, using a spanner of the right size preferably, or an adjustable, gently crack open the retaining nut on this valve to allow a gentle dribble. Just as gently carry on unscrewing it until it is away from its tail (the bit that goes into the radiator). You will get a dribble because there is an air lock inside the radiator. You have the option, if you are brave, to unscrew the bleed screw on the rad to hasten the flow of water from the radiator.
You will now know whether or not the lockshield valve is working because if you have shut it off completely, you will not get any water out of it.
After a short while, the water from the rad should stop, if it has then your TRV is working as well.
Place a second bowl under the TRV and undo that in the same way as the lockshield valve. Allo any remaing water to drain away.
Then gently lift the radiator off the brackets and tip towards one bowl to try to get rid of any remaining water.
Then, keeping the lower end over a bowl, tun the radiator UPSIDE DOWN and carry it outside. This prevents any water left in the rad from flooding the house whilst you move it.
Remove the brackets and allow the plasterer to get on with his work, whilst you flush out the radiator in the garden to get rid of some of the crud inside it.
Refitting? simple, refit brackets.
Offer radiator up to brackets and reconnect valves. Make sure all rubber seals (if there are any) are in place and there is no dirt etc on the interfaces between the valves and the tails.
Make sure the bleed screw is closed.
Make sure the system is off and check the pressure. A combi system should be at around 1 bar when turned off. As you are going to refill this radiator, then you can afford to stick another 0.5 bar into the system. Depending on how it's plumbed in, there may either be a flexible fill loop underneath the boiler or perhaps just pipework with a stopcock. In any case this will run from the rising main (near point of entry to boiler perhaps) to the pressurised heating system.
Once you have done this, carefully open the valves on the rad, checking for any leaks in the interfaces you've just rejoined, then bleed it.
If the pressure should drop below 1 bar whilst bleeding it, recharge the system up to 1.5 bar and carry on.
Bleed all the rads in the house.
Recheck pressure,
Turn system on to ensure the rad gets warm.
After a week or so try bleeding the rads again, just to make sure you've not moved an airpocket around.
Beware of the following:
The valves and associated fittings are Brass, not mild steel, so they can round off easily with a spammer if you're not careful. In my experience, stilsons etc are a last resort, especially when doing up valves. You will get much better results using a good adjustable or the right size spanner.
When undoing or doing up the valves,the valves themselves can turn, and bend the pipes they are attached to. You don't want this to happen. If this starts to happen, use a pair of grips to hold the valve still whilst you undo them.
The water that comes out of the rad can come out of carpets with carpet cleaner - yes I've found this out the hard way!
Hugo
Hugo
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Once the radiator is empty, disconnect the tails completely and lift the radiator off its brackets. Depending on its size you may need two people. WARNING when tipping the radiator some black sludge may drip out, this contains iron and will indelibly stain carpet and flooring.
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I agree that radiators are surprisingly heavy.
Further suggestions/warning about the dreaded sludge.
I always rollup some kitchen roll and plug up the two outlets and ensure the air bleed screw is shut before lifting the radiator. I have found that drained radiators can still contain a lot of liquid.
Further more of course do not flush the radiator onto anything that will stain. They usually need an awful lot of flushing before clean water emerges.
I hope YOU/two too emerge spotless.
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when you turn the trv to nil themostat wont work as its closed.
you will have to shut off both valves.and if you intend replacing one or both rad valves. system will have to be drained.
--
Was mech1
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Bloomin' nora.
I bet if I asked how to change a light bulb on this forum I'd get 18 responses, each more detailed and full of tales of woe or worse than the previous.
I love this place :o)
No Dosh - Backroom Moderator
mailto:moderators@honestjohn.co.uk
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AAh now changing a light bulb, that is REALLY tricky......
You see from next year you'll have to be qualified etc etc.
How's the Alfa?
Hugo
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AAh now changing a light bulb, that is REALLY tricky...... You see from next year you'll have to be qualified etc etc. How's the Alfa? Hugo
The Alfa is fine and dandy, thanks Hugo. They replaced a duff lead and flywheel RPM sensor and all is tickety boo.
Actually, being as it's a diesel it's tickety tickety tickety tickety vrooooom.
Anyone seen my coat? Ah there it is.....
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I dont do lightbulbs, thats unskilled work.
"Actually, being as it's a diesel it's tickety tickety tickety tickety vrooooom"
Shouldnt that be
tickety tickety tickety tickety vrooooom COUGH CHOKE silence
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I dont do lightbulbs, thats unskilled work.
"Actually, being as it's a diesel it's tickety tickety tickety tickety vrooooom"
Shouldnt that be
tickety tickety tickety tickety vrooooom COUGH CHOKE silence
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>>tickety tickety tickety tickety vrooooom COUGH CHOKE silence
Actually...
tickety tickety vrooooom COUGH CHOKE silence ring ring, ring ring, this is AA customer assistance, how can I help you ? Oh, hello Mr. Dosh, has it broken again ?
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Britannia actually, but the rest of it was just about spot on.
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"I bet if I asked how to change a light bulb on this forum I'd get 18 responses...."
Hey hang about, this forum doesn't have any light bulbs :)
groan
H
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Must emphasise balancing of the system. Not a lot of people know about that. If you are content with the heat output of the radiator then make sure you count the number of turns you make to shut off the valve (the other one - not the thermo type one).
Then use the same number of turns to open it up again when the work is finished.
This valve, and all the others in your home, diverts the appropriate proportion of hot water to each rad. Generally, the further the rad is along the system away from the boiler the more hot, and getting cooler, water flows through it.
Muck it up, like I have, and it could take weeks of trial and error fiddling about with valves to get it all spot on again.
That's my problem - it's that perfection thing going again.
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As I won't be fitting the new radiator, and it will be a different size & shape, hopefully that won't be my problem... And as it's my spare room I've never had the temperature above 'frost' so I don't know if it makes any sense. But thanks, I shall make sure that I remember that.
So does this mean that if I open the balance valve on the radiator elsewhere in the house that never seems to put out enough heat I may solve that problem?
What sort of a spanner am I supposed to use (I presume that my local plumbers merchant will know exactly what I need).
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Its very simple Map and don't be afraid of it. Turn the valves off and open the bleed screw. It will leak for a little while but then stop. That will tell you that the valves are closed and its OK to proceed.
As already stated with a low bowl underneath crack the union nut where it connects to the radiator on the lockshield valve. This is the very large nut closest to the rad. A large adjustable is ideal.
Most important is to use a pair of grips or similar on the valve body to avoid twisting the pipe.
Each time the bowl fills nip the nut back up whilst emptying the bowl. And just remember the black water which remains in the rad when lifting off the barckets.
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As I won't be fitting the new radiator, and it will be a different size & shape, hopefully that won't be my problem... And as it's my spare room I've never had the temperature above 'frost' so I don't know if it makes any sense. But thanks, I shall make sure that I remember that. So does this mean that if I open the balance valve on the radiator elsewhere in the house that never seems to put out enough heat I may solve that problem? What sort of a spanner am I supposed to use (I presume that my local plumbers merchant will know exactly what I need).
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Yes, up to a point. You may well fix the cold rad and have it running nice and warm - you'll just upset the flow further down the line. It may be fine or you may wish you had left it alone. I kid you not after re-doing my bathroom, moving and changing the rad, as well as one in the kitchen, it took me a couple of weeks of very slow trial and error to get them all as before.
I can't remember the spanner size offhand but it's small to go on top of the spindle - 1/4in or 4mm-ish.
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Sometimes, you dont need to remove the radiator. I have in the past been able to do this.
If you have enough slack on the feed pipes to the rad, then I turn off the valves undo the radiator nuts a 1/4 turn (they go the "wrong way" BTW), lift the radiator off its mounting lugs, and tip the top towards you and lay on the floor, tightening up the nuts again. There the rad stays while you work behind it.
When i have removed radiators I slip a balloon over the feed ends to catch any dreaded black gunge (and you WONT get this out of the carpet)slip ups during moving it.
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Doddle. Thanks for all the information, chaps, & the holes NOT to fall in. Old carpets are of course for mopping up the spills...
Incidentally, those end caps were almost £1 each (from plumbers merchant) which I thought was pretty steep, for all that they're brass. For the cost of 8 of them you can buy an electric drill in B&Q...
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Good to hear you survived ;-)
StarGazer
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Well it wasn't ever going to be very difficult to get it done, but top tips like counting the turns on the balance valve (fully on in my case, so I doubt it was done in a very sophisticated fashion!), and warning of the presence of black sludge in the bottom, reduced the amount of trial and error I had to go through.
I just have to hope it's all back in one piece before November...
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Well it wasn't ever going to be very difficult to get it done, but top tips like counting the turns on the balance valve (fully on in my case, so I doubt it was done in a very sophisticated fashion!), and warning of the presence of black sludge in the bottom, reduced the amount of trial and error I had to go through. I just have to hope it's all back in one piece before November...
I think 90% of the CH systems I have seen after professional installation are never balanced. It takes perhaps half a day and never seems to get done unless there is a problem getting flow to one particular radiator.
I.
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I think 90% of the CH systems I have seen after professional ...
Crumbs! Even on Mars?
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