"Christian McArdle" wrote in
:

(1) a common connection

I presume you mean 1 and 2, unless it was an air conditioning system you
were installing...

No, 1 and 3, I remembered how confusing the instructions were so I took it
off it's mount to check what I'd done.

The diagram gives no idea - I guess it's not a standard relay but some sort
of flip flop, and they have it marked as I said.

So I'm guessing 13 what they call "call for heat" is normally closed as in
my day things were drawn in the unenergised condition. 12 "heating
satisfied" has no use in my system, I suppose I could connect a light to it
to show the boiler isn't running.
The way they've drawn the contacts the heating woulld never start.

(Who'd a thought they could make it such hard work?)

mike