Cold radiator in attic

[stevepalace]

Hi I've searched all the pages and can't find an exact answer to this issue.

We have a sealed heating system with the hot water tank on the third floor and the boiler on the second. At the moment we have one radiator in the attic room (highest radiator) and it won't fully heat up. It is warm at the bottom but not as hot as the other radiators. I've tried to bleed it and open the valve and no air or water came out for 5 minutes. I then swapped the valve for a one way valve to allow air to pass out automatically but it hasn't made a difference.

Does it sound like an air block? Should i drain and refill the system? The boiler has been serviced and is a good size for the property but i forgot to ask the plumber when he was here!

Any help would be massively appreciated. Thanks

Steve

 

[CBW]

Is this a new issue, or has it always been a problem? What’s the pressure like?

 

[stevepalace]

We moved into the house about 18 months ago and it has always seemed to be an issue. I thought it was just air as it's the top radiator which is why i put the auto vent in. The pressure is 1.5 bar. thanks

 

[CBW]

Are both valves open?

 

[stevepalace]

yep

 

[Gasplumber]

Turn all rads off on 1 side trv is easiest if you got it and see if it heats up. And did you actually get the air out so water came out

 

[stevepalace]

Great, i'll try that..thanks

 

[stevepalace]

Hi so i turned off all the radiators bar the problem one and turned the heating on. The bottom of the radiator was roasting but the top was still just luke warm at best. I left it for 30 mins but no change. I then loosened the auto air valve (where the bleeding nipple was) to see if water or air or something would come out and nothing did. You could literally loosen the valve all the way (which may not be best practice with air coming in etc!!) and nothing was coming out even when the heating was on and the radiator for the bottom half was boiling. Is the radiator blocked? Would it help if i just drained the whole system? Should i change the radiator?

Many thanks for your help

 

[CBW]

What type of radiator is it? (Eg towel rail,column,standard)

 

[Madrab]

Shut off both valves, drain and remove the radiator then open the valve on each side into a bucket and check that there is good pressure on the flow and return. If you're not getting any air/water pressure at the rad's bleed screw then there's a blockage somewhere, or it's not piped correctly.

 

[stevepalace]

It's a standard radiator around 100cm wide. Right i'll try and flush it out fully. Cheers

 

[Madrab]

Just close off the valves, crack the nuts and bleed and drain the rad, leave it where it is and try opening each valve first.

 

[CBW]

Is any of the pipe to it plastic? It may have got kinked.

 

[stevepalace]

Thanks for ideas, no all pipe is copper and looks in good nick

 

[Gasplumber]

You could try tapping the radiatorhave you checked the valves yet to make sure you get water out them both!