siemens rdj10rf wiring to grant vortex pro external combi

[ollie78]

hi. need some help wiring a siemens rdj10rf programmable stat to a grant vortex combi. I'm not quite sure were to connect the common (lx) from the stat or if i need to. I've connected live to live, neutral to neutral, L1 (stat) to C.H terminal 1 (boiler). According to the grant manual i need to link LIVE to H.W terminal 2 in the boiler.
this just leaves LX (common) and L2 (Changeover contact) in the stat.
Hope i'm making sense...
thanks

 

[joesparks]

the stat often takes the place of a factory fitted link in the boiler and all the stat does is replace this short link (that is constantly closed and so making a circuit) with a longer link that opens on reaching set temp and closes to fire up the boiler (call for heat). use L1 and LX. Best to refer to boiler installation manual or get in touch with their technical department.