If you have had two valves that don't open, it is unlikely to be the valve. You say that the boiler is heating up the hot water and radiators when the valve is set to manual, so, the boiler appears OK. Based on that, if the valve isn't opening, then there is a problem with either the time control, (programmer) the room thermostat, or the wiring between them.
First of all, is your room thermostat battery operated? Does it need new batteries? Is it a wireless thermostat, and if so, is it paired to, and communicating with its receiver?
The next steps are quite easy for someone who is competent with a multimeter and able to use it safely to check. If you aren't, please engage the services of someone that is. To be meaningful, the tests will have to be done when the fault is present.
1. With the heating set 'on' is there 230v between the motorised valve's white wire (heating on) and blue wire (neutral)? there should be.
2. If not then check that the blue wire is actually connected to a neutral properly, and trace the white wire back to the room thermostat. Is there a live in and out fo the thermostat?
3. If there is not a live at the thermostat, then check the other end where it leaves the programmer.
Water dials on the front don't click when they hit the temperature as the have in the passed.
Boiler dials generally don't 'click' most are variable resistors (like the old rotary TV volume controls) that are hooked up to the boiler electronics, the switching is then done by relays on the circuit board. There is nothing in your post to suggest that there is a problem with the boiler.
