Hot Water but No Heating?

I have a Potterton Performa Eco HE.

I have hot water but no heating and cannot find the magical red button mentioned within this thread.

I wonder though whether I have a different problem.

The heating flow pipe ( #16 in the installation manual) is hot and the circulating pump is working, I can hear water passing through the radiators.

Hopefully someone can help.

Pitshanger
November 2017