Rads that used to work don't anymore Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Littletree]

We have oil central heating, supplying 11 rads in a bungalow. The boiler is situated centrally in the house. All rads are fitted with thermostats. When we moved in about 4 years ago all rads worked fine. However, each autumn/winter since, when we have put the heating back on, some rads have not worked. Was advised by a friend to knock the pipes feeding the rads and this worked on some but not others. All rad thermostats show they should be on. Rads that are not working are situated at varying distance from the boiler, some close, some further away. Currently 4 rads not working. Any suggestions?

[htg engineer]

Pump working and in good conditions ?

Turn pump speed up ?

Try removing the thermostatic radiator valve heads and make sure the pin in the top moves freely - press a few times and see if the heat improves.

Check lockshield valves are open, sometimes they are practically closed and will catch any sludge/debri etc.

I'll watch for your next post

[Littletree]

Pump ok. Lockshield valves appear to be open on all faulty rads. Not sure how to remove thermostatic radiator heads. Have tried to look up advice on this, but can't find any. Any suggestions?

[ianr]

Thermo rad valves are prone to sieze, even if they look to be in the on position they very often are closed, remove the thermo valve head if the brass plunger below does not move or show 1cm of its lenght you can try gently to encourage it to move with pliers or grips, with the thermo head off the valve should be in the open position allowing the hot water to flow, if the valve works after removing the head its a simple matter of changing the head of the valve, if not you may need to change the complete valve which will require draining and refilling the system