Radiators not staying on (bit like Marmitelover's thread)

[Aberchips]

We have recently moved into a new house, the boiler has been serviced by us & working fine. My problem is with the radiators - they all have thermostatic controls on & seem to be working. When the heating comes on the radiators do too, but they don't stay on all the time the heating is on. They seem to come on & warm up & then go off again. EG. the one in our bedroom is set to "2" on the thermostat valve and can be cold even though the heating is on. However if I then turn the valve up to "3" the radiator will come on again.
My old radiators didn't do this, they were just on all the time the heating was, but at different levels of hotness depending on where the thermostat valve was turned to.
Is this a different kind of system or have I got a problem with them?

you can set each radiator separately using the thermostat valves

Is there also a room thermostat somewhere that is set too low and turning the heating off too soon? I've had this when the kids have messed with the thermostat despite each radiator also having it's own thermostatic valve.

It sounds like you have a system where each radiator has its own little thermostat control, rather than you having a room thermostat?

If so, yes each one will make its own decision about shutting off when it's sensor says it's reached the right temperature. You may need to experiment a bit with what setting you want on each one to keep the rooms how you want them.

No there is just one room thermostat downstairs in the hallway (digital one) where I can see that the temp is below the required temp - heating is still on & the thermostat is calling for heat. The radiators downstairs can be on & the ones upstairs not?

on our old system, we had a similar room thermostat & all the time the heating was on the rads in each room were too.

It's more the fact that I can go into the room when the heating is on, the rads are cold, yet when I turn up the valve the come on again. Surely they should just be on at a certain level rather than coming on & going cold until you turn them up again?

Are they off simply because the room is warm enough?

They are supposed to do that. Turn the thermostats up of you want the rads to stay on.

www.seai.ie/Power_of_One/FAQ/Heating_Controls_and_Radiators/What_are_Thermostatic_Radiator_Valves_or_TRVs.html

The purpose of the thermostatic valve isn't to control the temp of the radiator, it is to turn the radiator off and on to keep the room at the temp you chose. Setting 2 is obviously too cold for your needs. Turn it up to 4 or 5.

If you turn a rad up, and the room gets to a comfortable temperature, then leave the control set where it is, will the room be warm when you come into it another time? (while the heating is still on in general of course).

If what's on each rad is a thermostat, then it will be making its own choices. But a radiator thermostat ought to be consistent, so when you find a setting you like, and leave it set to that, that's the temperature it should always shut off that particular radiator at.

A thermostat is different from the other sort of control that you find on radiators, the ones that are just a sort of 'tap' which can be opened and closed so you get 'lots' or 'some' or 'none' hot water flowing through it.

Ah ok - so I think I'm confusing what the valve should do! Apologies to everyone!!

How do I know if my thermostats are defintely that & not just a basic control?

goes off to google images of thermostats

Thanks for all the advice so far.