How do I know if Ive got sludge in my radiators?

[DIY-NOVICE]

My ground floor radiators are all cold at the bottom to some degree to worst has about 10 cms of hot at the top. Having read some of the posts I suspect that it may be sludge in the system but how would I tell?.
The boiler is less than a year old but the radiators are the same ones that were here when I moved in 10 years ago.

[Vivkins3]

I think there are some products available to buy which may or may not be effective. You have to get it into the system and run it though.

My hubby always takes radiators off when we decorate and empties out all the sheet and gunk. But I do realise he is a one-off.

[marabout]

i "bleed" my radiators before the onset of winter....starting with the ones furthest away from the tank...big towel! small bucket...using the radiator key...undo...slowly!...and allow the black water...from the bottom of the radiator...run free,until clear water starts to appear...use key to "shut off"!

[DIY-NOVICE]

thanks i can try that at the week end Ill keep my fingers crossed that it works

[buildersmate]

Bleeding the radiators doesn't generally do much to remove sludge - being heavier than water it stays at the bottom. The bleed valves are at the top and bleeding gets air or other gases out.
If you changed the boiler one year ago, any plumber worth his salt should have done this as part of the job, and any change like this will have stirred up any gunk in the system - that's why you have the problem now and not before.
There are a number of products on the market to remove sludge. Try one of the DIY sheds and just follow the instructions. A bit messy and time-consuming but worth it.

[gasman]

I dont think you need to confirm this, as it is a dead cert you have a build up of sludge. But if you want to find out for sure then you will have to either perform a chemical test to establish the level of inhibitor. If it is a low concentrate or non at all then you will have sludge problems. Or you can take off one of the rads you suspect and empty it into a bucket where you can then see if there is any sludge there it looks like old engine oil. And last off all you could always drain the system down and observe the final dregs that come out the hose pipe if it is black and oily looking and thick and slimey to the touch then it is sludge.

[Doc_Spock]

Bite the bullitt.

Close valves at each end of rads.

Open bleed nipple.
Undo vales from rad.
drain into pan, into bucket.
Flush rad out.

As some are hot at the top I suspect the pump is ok.

[DIY-NOVICE]

Thanks this has been loads of help, I'm off to B& Q to check out what products are available then I'm going to have a busy week end. I might be back for more advice but thnks to evryone for their input. Ill let you know how I get on.

[terence7556]

before spending money at b & q just consider the above advice, because most of the problem can be cured by your own labour
you will need inhibitor to protect the inside of your system to stop the sludge repeating its visit. sludge is black iron oxide caused by internal corrosion and i am surprised that you are suffering from it in a fairly short space of time
a good plumber will chemically clean the system before filling it with water that has inhibitor with it but you do not appear to have had this done and now have to take off the affected rads and literally hose them out in the garden ,say, with a hose pipe through the bottom connections to flush the sludge out.this is time consuming for you but not costly in terms of materials
the alternative is costly such as paying for a power flush by someone like b.gas. my wifes workmate was quoted �600 for this process but there may be cheaper alternatives from other plumbers
its not easy is it? you think after paying a lot of money for a new boiler that it would make things better not cause headaches like this

[DIY-NOVICE]

I am quite prepared to do this myself but am not sure how I am supposed to get an inhibitor into the system. I dont want to make a mistake and damage the system I am relativly confident about draining the radiator, but i'm not clear about how I get it off the wall and into the garden without damaging the pipes. Also do I drain the whole system at one time or do I do 1 radiator at a time. once I am happy that they are sludge free how do I add the inhibitor? and is there any special type of inhibitor or do they all do pretty much the same job.

[buildersmate]

It was me that suggested using sludge remover to you, but I do agree that if you are happy with the prospect of removing rads off the wall then it's a better solution.
You get the rads off the wall by unscrewing the 2 large nuts each end at the bottom. This allows enough leeway/movement from the pipes to lift the rad upwards off the wall brackets.
Its a lot simpler to drain down the system and do all rads together, one at a time. Drain down by finding the drain point at the lowest point in the pipe network. In a 4 bed house there may as much as 20 gallons (100 litres) of water in the sealed system. Some houses don't have a drain point low down - in which case you have to drain off using one of the downstairs rads. I do this by closing down both lockshield valves - one each end - on the first rad. This stops the water in the system from draining out and you only have to worry about the water in the rad you are working on. Then unscrew one end gradually and catch the water (having released the air bleed valve at the top of the rad to allow air in as the water level falls). You can turn the nut tighter again to stop the water flow to allow you to empty the receptacle. That way you are in control of what's happening. Eventually the flow stops and you can remove the other end nut. Beware - bottom of the rad is where the black gung is and more water/gung will come out as soon as the rad is lifted slightly at one end! Use old sheets etc. to be safe with carpets.
Having got one rad off, you can drain the rest of the system by releasing gently the lockshield and catching the water. Do both ends in turn.
Remove each rad in turn, take outside to wash gunk out and replace.

[buildersmate]

Depending whether you have a pressurised sealed system or a open system with a small header tank (which you obviously tied up at start, to stop water refilling as you drained!), the inhibitor either goes in the header tank, or you use a valve to 'squirt' inhibitor concentrate into one of the rads after reconnecting but before refilling with plain water. Inhibitor is water soluble and it soon mixes so it doesn't matter where you inject it.

[buildersmate]

Inhibitors are much the same - this is the one I use by Sentinel - X100 (scroll down). Its widely available.
http://www.discountedheating.co.uk/shop/acatal og/Online_Catalogue_Sentinel_1020.html

[DIY-NOVICE]

thank you all for your help esp builders mate I checked out the link, great stuff I am feeling much more confident. cheers

[Surreyplumber]

You could have the system power flushed by a member of the PowerFlush Association they will use chemicals that should work. If power flushing does not work, you could have it powder flushed. It works great on hardened sludge and micro bore.