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[Help] HELP: Draining a radiator. What am I doing wrong?



Tom Hark Preston Park

Will Post For Cash
Jul 6, 2003
72,714
So it appears the fault isn't in my workmanship but in the radiator itself. I'll try [MENTION=205]Tom Hark, Preston Park[/MENTION] 's unintentional piece of good advice.
Would it be more likely the thermostat valve causing the problem?

Thinking of setting up an NSC OFFICIAL Helpline actually on the strength of my latest success. Working title: Tom'll Fix It ("Had An Accident In The Home That May Not Have Been Entirely Your Fault?") :thumbsup:
 
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marlowe

Well-known member
Dec 13, 2015
4,343
You flatter yourself.
You do realise that the bleed valve is for removing air, not water?

I do but I cant help it if water comes out of it. I only opened it so that the water would come out of the connecting valve at the bottom more easily.
 


golddene

Well-known member
Jul 28, 2012
2,022
Ridiculous to suggest all that work for that improbable theory.
OP does the radiator go cold when the valve is closed? If so, how can both valves be faulty?

Freeze kits are only for people who know what they're doing and have done it before.
we all have to learn sometime mate, i've used the freeze method once to do exactly what the op is doing with great success, but its not for all if you are not too savvy, as for draining the system, the advantages are less water to risk spilling over carpets etc, personally I have a combination system where just turning off the main supply stops water to the system and refilling is a doddle using the integrated refill pipe and valves. Obviously having to fiddle around with header tank etc is a bit more work but nothing that would bother me.
 




marlowe

Well-known member
Dec 13, 2015
4,343
probably one or both valves are failing? easiest way would be to drain the entire system, do your repairs then replace the valves (£10) prior to re fixing and refilling the system and bleeding the whole system, failing that toolstation/screwfix sell a freeze kit which you can freeze the pipes both sides of the offending radiator and hurriedly carry out your repairs. id drain the system personally. good luck.

Thanks for the advice but I'm not exactly known for the speed in which I undertake jobs, coupled with the fact that I'm not an experienced plumber so any job requiring a time limit under those circumstances is a disaster waiting to happen. It's one of the reasons I never use quick setting cement.
 


SIMMO SAYS

Well-known member
Jul 31, 2012
11,750
Incommunicado
The return valve looks like its been leaking but could still be ok.
The flow valve is set on frost so should be off but could be letting by.
You may have to bite the bullet and drain the system and change both valves.
Or PM [MENTION=26444]Wrong Direction[/MENTION]
 


LamieRobertson

Not awoke
Feb 3, 2008
48,708
SHOREHAM BY SEA
Thanks. I did have him in mind when I posted. He's helped me out in the past with previous plumbing advice. I know he's retired now but hopefully that doesn't extend to imparting his knowledge and expertise on internet football forums.

Apparently Mrs Simmo has banned him from NSC today

Edit he’s been given five minutes :moo:
 




HAILSHAM SEAGULL

Well-known member
Nov 9, 2009
10,360
If you have closed the two valves in picture 2, you then need to have a couple of containers underneath the unscrewed nuts in picture 3 to catch all the water that is inside the rad.
Be prepared to finger tighten the nut to stop the flow whilst changing containers as they fill up, there is a suprising amount of water in a rad.
When the flow stops, lift the rad off the wall brackets carefully, keeping it level, then tip the the mucky water at the bottom of the rad into a bucket/bowl. this is the water below the nut line.
I suggest you put down a couple of old sheets cos there is bound to be some spillage.
The air release/bleed valve in picture 4 and the temperature valve in picture 1 shouldnt have any thing to do with the draining down I think.
I' not a plumber, but this is how ive had to remove mine for decorating etc,
 


marlowe

Well-known member
Dec 13, 2015
4,343
The return valve looks like its been leaking but could still be ok.
The flow valve is set on frost so should be off but could be letting by.
You may have to bite the bullet and drain the system and change both valves.
Or PM [MENTION=26444]Wrong Direction[/MENTION]

If I switch on the central heating system with both valves set to off and the radiator gets hot will that tell me that the flow valve is letting in water and therein lies the problem?
 


SIMMO SAYS

Well-known member
Jul 31, 2012
11,750
Incommunicado
If I switch on the central heating system with both valves set to off and the radiator gets hot will that tell me that the flow valve is letting in water and therein lies the problem?

If one valve is faulty and the other is ok and off the radiator will still not have a flow through it so no.
 








BN9 BHA

DOCKERS
NSC Patron
Jul 14, 2013
22,864
Newhaven
So it appears the fault isn't in my workmanship but in the radiator itself. I'll try [MENTION=205]Tom Hark, Preston Park[/MENTION] 's unintentional piece of good advice.
Would it be more likely the thermostat valve causing the problem?

Hello marlow, yes I would say the thermostatic radiator valve ( TRV ) is not shutting down, that make seems to have an issue with this after a while. I have changed lots of this type that won't work when needed.

There is one trick of the trade that may work but it will cost you the sum of 5p.
Make sure the other valve ( lock shield ) is still turned off, open up the TRV to 5, remove the TRV head ( large chrome ring ) with some grips.
You will now see a pin, dead centre of the TRV, this is what isn't moving. Get a 5p coin and try and put this on the pin, then refit the TRV head, may take a few goes.
Then shut the TRV off to setting zero and carry on as before.

This may work, it has for me.

EDIT- If the TRV is a Drayton the 5p coin is too big, sorry I've just checked this on one I had in my garage.
Try a small piece of metal that's smaller than a 5p coin.

Sorry the 5p works on some makes of TRV but not all.
You just need something under the TRV head to push down the pin in the valve to fully close it.
 
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SIMMO SAYS

Well-known member
Jul 31, 2012
11,750
Incommunicado
Hello marlow, yes I would say the thermostatic radiator valve ( TRV ) is not shutting down, that make seems to have an issue with this after a while. I have changed lots of this type that won't work when needed.

There is one trick of the trade that may work but it will cost you the sum of 5p.
Make sure the other valve ( lock shield ) is still turned off, open up the TRV to 5, remove the TRV head ( large chrome ring ) with some grips.
You will now see a pin, dead centre of the TRV, this is what isn't moving. Get a 5p coin and try and put this on the pin, then refit the TRV head, may take a few goes.
Then shut the TRV off to setting zero and carry on as before.

This may work, it has for me.

EDIT- If the TRV is a Drayton the 5p coin is too big, sorry I've just checked this on one I had in my garage.
Try a small piece of metal that's smaller than a 5p coin.

Sorry the 5p works on some makes of TRV but not all.
You just need something under the TRV head to push down the pin in the valve to fully close it.


I've warned you about being too helpful:wink:
 




Baldseagull

Well-known member
Jan 26, 2012
11,839
Crawley
Could be there is nothing wrong with the valves and there is just some pressure in the rad if it is a pressurised system. Let the water run from the bleed valve for a bit and see if it slows down and stops. Other thing, if it is ok, shut the bleed valve when you undo the nuts on the rad tails, if it is open the water will gush out and be difficult to catch it all, after a while when the flow slows, open it up a tiny bit at a time.
 


marlowe

Well-known member
Dec 13, 2015
4,343
Hello marlow, yes I would say the thermostatic radiator valve ( TRV ) is not shutting down, that make seems to have an issue with this after a while. I have changed lots of this type that won't work when needed.

There is one trick of the trade that may work but it will cost you the sum of 5p.
Make sure the other valve ( lock shield ) is still turned off, open up the TRV to 5, remove the TRV head ( large chrome ring ) with some grips.
You will now see a pin, dead centre of the TRV, this is what isn't moving. Get a 5p coin and try and put this on the pin, then refit the TRV head, may take a few goes.
Then shut the TRV off to setting zero and carry on as before.

This may work, it has for me.

EDIT- If the TRV is a Drayton the 5p coin is too big, sorry I've just checked this on one I had in my garage.
Try a small piece of metal that's smaller than a 5p coin.

Sorry the 5p works on some makes of TRV but not all.
You just need something under the TRV head to push down the pin in the valve to fully close it.

Ok thanks. I'll try that when I'm next there, possibly tomorrow. I've asked her to open up the thermostat valve to max setting with the other valve turned off to see if it heats up. If it does it suggests the other valve (lock shield?) is the problem and is stuck open(I think that's right). If not it suggests it is the thermostat valve as you suggest. Just waiting for her to report back to me to see if it has heated up.
 




marlowe

Well-known member
Dec 13, 2015
4,343
Could be there is nothing wrong with the valves and there is just some pressure in the rad if it is a pressurised system. Let the water run from the bleed valve for a bit and see if it slows down and stops. Other thing, if it is ok, shut the bleed valve when you undo the nuts on the rad tails, if it is open the water will gush out and be difficult to catch it all, after a while when the flow slows, open it up a tiny bit at a time.

No, I tried that yesterday and it didn't slow down or stop. Just kept spurting at the same pressure.
 


Bry Nylon

Test your smoke alarm
Helpful Moderator
Jul 21, 2003
20,670
Playing snooker
Hello marlow, yes I would say the thermostatic radiator valve ( TRV ) is not shutting down, that make seems to have an issue with this after a while. I have changed lots of this type that won't work when needed.

There is one trick of the trade that may work but it will cost you the sum of 5p.
Make sure the other valve ( lock shield ) is still turned off, open up the TRV to 5, remove the TRV head ( large chrome ring ) with some grips.
You will now see a pin, dead centre of the TRV, this is what isn't moving. Get a 5p coin and try and put this on the pin, then refit the TRV head, may take a few goes.
Then shut the TRV off to setting zero and carry on as before.

This may work, it has for me.

EDIT- If the TRV is a Drayton the 5p coin is too big, sorry I've just checked this on one I had in my garage.
Try a small piece of metal that's smaller than a 5p coin.

Sorry the 5p works on some makes of TRV but not all.
You just need something under the TRV head to push down the pin in the valve to fully close it.

:mad:

Alternatively, just put on another jumper
 


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