How can I override a Siemens RDJ10RF programmable room thermostat?

[Cora Trigari]

hi there,
I've the Siemens room thermostat which hasn't properly worked for the last few years i.e. Intermittent activity as programmed, then nothing. I've gotten round this by just overridding the receiver unit that is wired into the boiler however tonight even this isn't working!
Is there anyway to bypass the receiver unit albeit I'm no electrican?
The only difference from last year is that the room unit has had batteries replaced in it (they ran out last year and I didn't replace them). Could this be the problem re the override function and resolved by taking the batteries out, effectively disabling the room unit?
Any help most appreciated, thank you

 

[Laylaapj]

Hi, if you don't mind me asking. It how was you turning the heating on with out the thermostat please? I have recently smashed the screen to my thermostat. Do I need to replace it straight away or. An I put the heating on without it.

Thanks.