After serious thinking rick wrote :
On 26/05/2017 21:42, Harry Bloomfield wrote:
Tim+ explained :
Interestingly, the modern way to do it is to have one regulator for both
fuels. I guess this means that heat output must be higher on butane.

That is correct - the OP is wrong, for the same flame size butane will be
the hotter.


Not me .. saying it is hotter .. just what is posted on many sites ...

http://www.infomania.co.uk/archives/234

You are mis-reading it quote..
'A given quantity of butane will burn hotter than propane but in fact
propane regulators release the gas at a higher rate to compensate.'

As I said, butane burns hotter than propane.