Radiator TRVs cutting out too early

[dnwilliams]

I've recently moved into a new flat which has radiators with TRVs and a single digital thermostat controlling the boiler in the hallway. The TRVs are the Drayton RT212 lockshield & push and fit packs (cheapy ones). Every TRV in the house is set at the maximum, 6, and the alledged sensitivity range is up to 29C. However, all of them cut the flow off at around 20C meaning that I cannot maintain a temperature above this in the flat (I'd ideally like 22C).

It is not a problem with the system as if I remove the TRVs completely in say the living room, opening the flow up fully to the radiators there, within 30 mins the temperate is up to 23C and climbing.

So, my question- is this normal? I would have expected even cheapy TRVs set at 6 to basically keep the flow open. If not, what is wrong? they are all installed exactly the same way and when I remove any of them I see no additional possibily for adjustment on the head besides the twist setting.

I should note that they are all fitted upright rather than perpendicular to the radiators, I understand that this makes them over sense the temperature- but should they really be cutting out at 20C?

thanks in advance!

David

[Harry Bloomfield]

[e-mail] has brought this to us :

Could you pack the outer fixing ring up a bit, to increase the temperature range?

[EricP]

Wickes normally have bins of TRV heads in for about £5 each. Go buy a couple and replace the old ones and see if it makes a difference. Cheap valves may need replacing every 5 years when they cease to function.