Replacing thermostat

[Vegas_Steve]

Hi I am trying to replace my thermostat, a Drayton RTS 1 with a Honeywell DT90E. Looking to check the correct wiring for the new thermostat.

This is the current one

and this is what I’m looking to replace it with if someone can confirm the correct wiring

 

[RandomGrinch]

Brown (Live) to A
Black (Switched Live) to B

...and a separate terminal block to safely isolate and protect the grey (neutral) wire, keeping it out of the way.

 

[Vegas_Steve]

Thanks, would have went grey to B as it was on the old one which is why I wanted to check

 

[RandomGrinch]

would have went grey to B

The N on the diagram sometimes causes confusion - there is a rectangle next to it. This represents the boiler (or other load).
The Live supply to the boiler is provided by B and to complete the circuit, you also need a neutral to the boiler - this is what the N signifies (as the boilers already wired up to a neutral, that's nothing you need to worry about!).
Does that make sense?

If you connected Neutral to B, there may have been a bit of a bang, the first time the thermostat called for heat!

 

[Vegas_Steve]

Thanks, very confusing but trying to get my head round it,