Hi both, thanks for the reply.
This did not happen with the previous stat, all worked ok. The controller is a ST699.
I identified the live and switched live from the wiring instructions of the old stat and also confirmed on the web but it shouldn't have power if the controller is off so...
Thanks for the reply, yes only just installed it and room temperature stated is 18 degrees. If I manually set the target temperature to 18.5 degrees, I hear the heating system kick in and the rads start getting warm and continues until temperature is reached and over runs slightly.
My problem...
I have just fitted a DT90E thermostat to me system replacing a T6360B.
All is well, with the wiring as it had four wires bit I removed the earth and neutral to install the DT90E so only have live and switched live now.
My problem is that even though the timer I see off, I can turn on the heating...
I need to fit a pump for my shower, it is on the same level as my hot water tank but is supplied via 15mm pipe approx 11 metres run (this is all this pipe supplies). Cold water is off the cw tank and approx 8 metres from pump also 15mm pipe. Is this ok, I have read pumps need 22mm pipe supply...