Boiler ignoring room stat

[oldguy]

Ideal classic boiler is ignoring room stat for the CH. when the CH is on alone and i turn the stat right down the boiler just keeps on going. The HW is working fine and obeys the programmer times etc. The CH also working to times as per programmer.
The room stat has three wires from it, yellow, blue and red. How can i check that the room stat is Ok ?

Had a new programer and motorised valve fitted last year so i'm assuming its nothing to do with those

thanks

 

[petit_pablo]

The programmer puts 230v power to the room stat when calling for heat on the red wire. When the stat is calling, power goes back down the yellow to the valve.

If you remove the room stat, the heating should not come on. It does sound more like the valve giving grief.