Room thermostat not getting 230v

[Phil_in_Swansea]

Hi folks. Posted this on electrics but probably should have posted here first...

In the midst of redecorating I thought I'd change my old BG RS2 room thermostat for a newer Drayton rts2. Three wire plus earth, easy swap right, nope. Turns out my room stat isn't getting 230v, just 205v.
Wiring runs mains to block (234v) block to Drayton lifestyle 522, 522 to block (different L + N points ) block to Room stat.
After the 522 the voltage drops to 205v which may explain why the new electronic Rts2 won't work properly.

Help please, any ideas or easy fixes very much appreciated.
Thanks
Phil

 

[ianmcd]

if your RTs2 doesnt click when you turn it you have lost a neutral