Hi , are you using a room stat as well or just the programmer? If just the programmer, then run a 3 core cable from boiler to the programmer. Live and neutral from boiler to programmer. 4 out from prog( heating on ) into switched live in boiler
The boiler has got a 24 hour mechanical time clock fitted when I remove this I take it I will have to replace the links I took out when I fitted the mechanical time clock.