So could be valve, could be head, could be installation method head to valve, or even way boiler switches on/off. So question is how to work out which is faulty, if in fact there is a fault.
So Bosch boiler with two thermostats one in kitchen and one in hall both in parallel hall one with a programmer and kitchen programmable idea is to prolong the morning boiler run so rooms can heat up, then kitchen one switches off.
There are 8 TRV's in the house, and two towel rails and radiator in airing cupboard without a TRV. Of the eight four have Energenie MiHome electronic heads, so two of the three bedrooms, living room and hall.
Hall wall thermostat set 18°C the TRV in hall odd one out, only one not Honeywell VT15, also set 18°C, and the computer reports hall at 18°C nine times out of ten.
Now I fully accept if boiler not running then radiators can't heat up, so bedrooms or living room under temperature from time to time expected, however I find the rooms over temperature and radiators still warm, this seems wrong.
The motor on the TRV takes time to close, so it could simply be valve opens when boiler not running then by time it closes radiator is hot, I assume need to close the lock shield valve so radiator warms up slower, or it could be seats faulty in valve and water still flows, this would mean changing valve, or wrong spacer in valve so head can't push valve fully home. The latter I think unlikely as when fitted as if reached fully closed I could hear motor strain.
But question is how to work out what is wrong. The wife's bedroom always hot, so slowly reducing lock shield valve setting, but other two rooms are some times cold and some times hot, so loathed to reduce lock shield valve settings.
I except the wax sensor with standard head is a bit hit and miss, but rooms with them in either hardly ever used or so small leave the door open for a few minutes and it will soon cool or heat, top of stairs only ever turns on when very cold as warm air comes up the stairs.
So any thoughts and comments welcome.