Radiators hot at top, cold at bottom

29 Dec 2006
Reaction score
United Kingdom

The problem I am having is that all the downstairs radiators are hot at the top and cold at the bottom. The double radiators are also cooler on the inner than the outer rad.

The temperature difference is quite large with the top being as hot as the upstairs rads and the bottom cold to the touch.

All the rads upstairs are working normally.

There is a conventional boiler in the kitchen with a danfoss pump next to it.
I can hear/feel the pump start, stop and run when I switch it on and off.

Nothing has been done to the system prior to this fault.

Any ideas?

Sponsored Links
sludge in system blocking radiators

add slugde remover for a week

drain system but check if radiators have started to get warm before you drain . if this is the case just add inhibitor and away you go

if not take each rad off the wall and spray a hose in to one end of the rad hoping to clear the blockage out if this doesnt work you may need new radiators as sometime the sludge can become hard in the rads and even powerflushing wont remove this problem

i would advise a magnaclean to be installed at the same time as draining down as this will help keep the system clean and is a good filling point to add inhibitor in the future
Sponsored Links
Take the silver screw out of pump, if it is black inside, system full of crap.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local