if the room stat is clicking then it is probably OK
it is more likly the motorised valve it operates
please see types of systems (fully Pumped) od www.gascentralheatinguk.info
Gasman, January 2009
When the house is cold can you here a click from the room stat when you turn it up and down. I am assuming it is a conventional type of room stat, if it doesnt then the likelyhood is it needs replacing
