Protecting a boiler with a relay

[Deleted member 26818]

No.
You got from ‘Boiler to external pump connections’ to terminals A1 and A2 correct.
You got terminals 4 and 2 to external pump correct.
The power to terminals 1 and 3 has to come from another source (preferably the same source as supplies the boiler).

 

[Deleted member 26818]

I hope this explains:

Top FCU has whatever fuse is recommended for the boiler (3A?).
Lower FCU (13A?).

 

[Harry Palmer]

I hope this explains:
View attachment 39611
Top FCU has whatever fuse is recommended for the boiler (3A?).
Lower FCU (13A?).

I undertand where i went wrong, again thank you spinlondon for the wiring diagram and of course taking the much appreciated time to reply