1 cold radiator

[dean]

i had a full central heating system installed 12 mths ago.When i put it on this winter 2 radiators downstairs were cold after balancing them they worked.The next night we put the heating on again and this time 1 radiator was cold,when i turned the thermostat on the radiator down that was cold and then turned it up again after 5 mins it became hot.Do you know what might be causing this problem.

[The Heating Doctor]

Are you sure the thermostatic radiator valves (trv's) are not simply just doing there jobs, when the room reaches the temperature the trv's are set to they close and the radiator cools down until the room requires more heat, they then open and the radiator gets hot again, and the cycle is repeated.

[dean]

The rooms were cold we had been out all day,like i said before all other radiators were hot but living room one was cold.