Siemens Rwb2e boiler control

[pleasehelp]

Hi all.
My mums boiler has a Siemens rwb2e.
it is still working when asking for hot water. But there is no response when turning the central heating on. I can not hear any noises (clicks) within the control box when asking for central heating (but can when doing the hot water).

Is there a way of me being 100% sure that it is the control unit rather than a boiler part. I’m fairly confident I can replace the box but want to be sure before I buy one.

I have a multi meter but not sure how I’d check this to be sure if anyone can give guidance? Thanks

 

[Wannabebetter]

I think this is right:

Turn power off to programmer, remove programmer, place a link wire between the live and heating on, turn on power, if the heating comes on then I’d say faulty programmer.

Edited: Thanks to Hugh pointing something out (though I had already said turn the power off ), the next part you could test is the room thermostat is getting live.

 

[Hugh Jaleak]

Do NOT remove/replace programmer onto backplate without isolating the power first.

Could do with more info on your system, the RWB2e is generally a reliable unit in my experience, you may be better trying to test for power output from it when 'Heating On' selected further along the line.