Radiator cold at bottom warm up top. Ideas?

[cruyff73]

Relatively new boiler (6 months or so) rads are warm up top but cold at the bottom. When boiler was installed I was told they'd flushed through the system to remove any sludge. Installer is now increasingly difficult to contact. Anyone got any ideas.

Cheers

 

[PSP-Paul]

Don't know if i'm allowed to answer questins here, but I always thought that problem was due to them needing to be bled?

There is a screw, or bleed key nut at the top of the rad, unscrew it slightly and air wil hiss out, then eventually water will start to spit out. BUT BE WARNED...the water is black, very black so I always wrap a towel around the screw driver (or bleed key). That way I don't get black carpets.

Mine need doing quite often. Don't know why.

I'd maybe get a professionals answer first though!

 

[cruyff73]

I always thought that the rads needed bleeding when it was the other way round (ie cold at top warm down bottom) but not too sure. Will give it a go anyhow!

Cheers

 

[PSP-Paul]

Oh yeah, thats true, think I read your post wrong, sorry mate!

It may well be something completley different then.

 

[cruyff73]

Just noticed there's a few topics on the same subject so must be a common issue. Apologies for that (I should've searched the forum first)

 

[JohnD]

...the water is black, very black ....
........Mine need doing quite often....

Paul - this indicates that your pipes and radiators are corroding. You need a corrosion inhibitor, such as Sentinel, in the water to stop it happening any more. It would also be an advantage to clear out the black sediment that will have accumulated in the system with a good flush and a chemical clean (Sentinel do them as well) and both are available at your DIT shed or plumbers merchant, or at a good price from Screwfix. A one litre bottle of each is enough for most houses.

You have to put put in new inhibitor after flushing or draining.