Some valves are flow direction dependant and if installed the wrong way around will make a chattering noise as the room approaches the selected temperature. (The valve is trying to close against an opposing flow of water)
This would be the first thing to check. This type of valve will usually has an arrow on the valve body marking the direction of water flow.
Even bi-directional TRVs (an arrow pointing out of each port) will chatter if the pressure difference across the valve is too high. This is usually caused by incorrect balancing.
The lack of an auto bypass or incorrect settings are the most common cause although the problem can usually be bypassed by balancing of the always open rad if there is one.
Do you have TRVs on EVERY rad?
If so do you have a AUTO bypass?
Sometimes poor quality installers fit a bypass pipe with a manual valve on it. Adjusting that can also prevent chattering but a manual bypass can also create other problems which is why an auto bypass should be fitted.
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