Radiators - cold at the bottom??

Barack Obama

Hi. Since switching the heating back on for these cold nights, the house isn't heating properly. I've just felt the rads downstairs and they are all hot across the top but cold at the bottom. The boiler (upgraded high efficiency gas) appears to be fine and is heating the water without any problems.

Any suggestions? I'm stumped because this appears to be the opposite of air in the system, right?

Thanks

Lenny

quick search, this topic seems related
http://www.boards.ie/vbulletin/showthread.php?t=2056129328

cikearney

system is full of sludge, a build up af loose steel particals from the rads, and deoxigenated water, this coats rads and pipe work and is a night mare. It needs to be removed, flushed out, and rads and cylinder may even need replaced

BorneTobyWilde

Geez let the air out of them,
Lil release valve at back of rad at top
Need a radiator key
like this



Open valve you will hear air come out, once water starts coming out shut valve,

cikearney

If the rads air cold at the top, they are full of air, thus the need for vent keys, this poster is experiencing the opposite, cold on the bottom

TPM

Check the what your room stat is set at, the rads heating at the top and not the bottom can be caused by the heating water circulating enough.
room stat set too low
circulating pump faulty/airlocked

sludge can cause rads not to heat properly, if often shows up as cold spots in rads, hot at top bottom cold in middle, cold at one end.

lezor

You say all of them are the same, every rad. Does the pump seem okay? and is the hot water cylinder heating as normal?