I have just recently had my central heating checked after a few radiator TRV's had become stuck. The engineer turned all TRV's and boiler's thermostat on maximum he said to run the system. Since then I have had to reajust all the TRV's to practically off and the boiler thermostat is well below minimum but the radiators still stay very hot (can smell the metal) I can not regulate the temparatures anymore. Can any body please help with an expanation.

Jane, October 2009

The boiler has a thermostat to tell it how hot to make the water. The hot water is pumped into the radiators until the TRV on the radiator shuts it off - the temperature of the water in the radiator will be determined by the temperature setting of the boiler stat. The system will continue to pump central heating water around the pipes until the Room Thermostat tells it to stop. If the boiler stat is high the radiators will get very hot. My boiler stat is marked from Zero (off) up to 6 (Max) - I run it just below 3.

Look to the Temperature control on your boiler first - set it to the mid position - then readjust the TRVs in each room to make your house comfortable. The smell you detect is very probably the paint rather than the metal.

Good luck...

Peccavi, October 2009

I suspect that the boilers thermostat has stuck on high, as you have it turned down to below the minimum - which should almost turn the heating off. I guess now the boiler is more or less running constantly?
This isn't the way to deal with stuck TRV's, by the way. I'm also wondering if plumber man has opened all of the lockshield valves on the other end of the rads, maybe unbalancing the system.

John, October 2009