my grn flr rad are cold at the bottom warm on top, why?

[ravb]

Hi

I hope you can help

i have 4 radiators upstairs which a re very hot, and 6 radiators on ground floor. the 2 radiators on the ground floor are warm on top, but cold on bottom. the flow in is very hot, but the return is cold. what can i do to sort that out? i have bled the radiator, one of them is ok, the other is trickling with water. is there a blockage in the rads? should i remove them adn clean them?

please advise.

thanks

 

[Agile]

Probably a sludge problem especially if each is fed from drop pipes from above.

You need to remove each rad in turn, clean it out in the garden and do a bucket test ( see FAQ ) on each valve.

Tony

 

[MANDATE]

Before doing anything, check the lockshield valve, if this is almost closed this could restrict the flow to almost nothing. When pump is not running and water not circulating, hot water in the radiator will rise leaving the bottom a little cooler.
It is more likely however that there is a blockage at the bottom of the radiator, so yes remove and clean.

 

[ravb]

thanks, i will give that a go.

i jsut wanted to also ask i have a combi boiler that was instaleld recently and have used the system for about 10 weekas or so and no inhibitor has been put in, woudl that have damaged the system?

im looking to drain the system and put in x100 inhibitor in there, it is a sealed system with 8 rads, will 1 litre be enough?

thansk in advance.