Honetwell BD91 to Nest

[Ian666]

Need some help please trying to replace my Honeywell with the new Nest on my Baxi combi boiler.
The wiring on the Honeywell is

N - 240v neutral
L - 240v positive
A - 240v
B - 25v
C - not connected

The wiring on the Nest I know is

N - 240v negative
L - 240v positive
1, 2, 3, I have no idea how to wire these.

 

[ericmark]

If you can't work that out, time you got some one in to do it.

 

[Ian666]

Look thanks for the help. I am skilled electronics engineer not a gas safe heating engineer. I know enough not to wire 240v where it isn't supposed to go. I have looked at all the information i can find and at this stage am a little confused (don't take much I hear you say)
So you are basically saying wire 240v to 2 and 25v to 3 on the hive?

many thanks for any help, sat here with it hanging on the wires on the wall!

 

[Ian666]

Another note, the Hive wiring instructions say to loop connect terminal 1 and 2 ?

 

[flameport]

Hive wiring instructions say to loop connect terminal 1 and 2 ?

They do not, because that would just connect the common and the rarely used normally closed switch contacts together permanently.

L&N / L&N are the mains supply to the device
A&B / 2&3 are the normally open contacts which are used to activate the boiler.

 

[ianmcd]

Another note, the Hive wiring instructions say to loop connect terminal 1 and 2 ?

Why are you quoting Hive wiring instructions when you are fitting a Nest ? Do not make any links

 

[CBW]

Where are you getting 25v mixed with 240v from?

 

[ericmark]

I see a picture of Nest call Hive.jpg I answered assuming Nest, if Hive my answer is wrong.