Bit of a strange one or I'm being stupid (I'll let you decide!) New boiler installed in my house tonight. From the switched spur to boiler 3 core LNE, the boiler to a JB have a 4 core cable (live out, neutral out,earth & return to boiler), from here a 3 core & earth to the programmer (Live Neutral & Return from the stat), from the programmer out to the stat ( switched Live, Neutral & return which is joined in the JB) the problem being when the programmer is powered up the live boiler is on, this is without the CH boost or any setting calling for heat on) I thought it's maybe a faulty programmer as when I take the programmer off there ain't 240 coming back in the return. Any help would be greatly appreciated but I'm thinking it's the programmer?