lockout reset wiring

Words of wisdom gratefully received please! I have a Vokera Maxin 24e combi boiler supplying 7 double radiators, one kitchen mixer tap, one bathroom sink mixer tap and one bath mixer tap with shower attachment. Boiler last had a major overhaul 9 years ago when I bought the property (it wasn't...

There are four terminals on the rear of a lockout reset button switch. on the left are two terminals, one above the other, each marked with an arrow (a shaft with arrow head), pointing in opposite directions from each other in between them is "A", on the right are the other two terminals one...