Correct wiring for programmable room thermostat

[JohnNN]

Hello,
I have a regular boiler doing room heating only, with a Drayton programmer (for time) + a Drayton dial stat (for temp).
I've bought a Honeywell T3 programmable stat to set diff temps at diff times.
Old Drayton stat (mains powered) had 3 wires (red, blue, yellow) + E (see pic)
New Honeywell stat (battery powered) seems to require 2 wires (marked A and B) and no E (see pic)
My thinking is that Red and Yellow are line in and line out, and that Blue was either used for powering the stat or for an "accelerator resistor". Image inside new stat (but not in instructions, see pic) seems to suggest something connected to N, so maybe that is still required?
Do I connect Red to A, Yellow to B and separately put terminal blocks on Blue and E?
Thanks for help, John

 

[Avo Mk8]

Yes your suggestion is spot on.

But to follow the wiring diagram you show, I'd actually put the red in "B" and the yellow in "A", but it's a very minor point. Just avoids having terminal "C" live when the thermostat is off.
N is not required by your battery powered T3. (The label diagram shows the load (boiler) as the rectangle symbol with N connected to it)
As you say - terminate each of the other two to insulate them from everything around!

 

[JohnNN]

Many thanks for the quick and helpful reply. I've done as you suggested and all is working well. I'll assume there isn't an issue with leaving my old programmer set to heating on permanently.