The message . com
from "Iknownothing" contains these words:

When it is just set to heat water, then we
do get nice piping hot water, but when it is set to hot water and
heating then only hot water, no heat.

Find the pump. Somewhere near that should be a thing that looks like this...

http://www.plumbworld.co.uk/images/pwhv0012s.jpg

This is your three-port valve which allows the controls to send hot
water from the boiler from the stem of the tee to either or both of the
side ports. One will be the CH, the other the HW.

There's a tell-tale lever on the side. Check that it's moving when you
move the switches on the timer.

--
Skipweasel
Pay no attention to that man behind the curtain.