I am having the same problem and have done for three weeks. Only the Boiler light is lit. We have had the circuit board changed, the thermaflow(?), the pressure switch, pretty much every thing. It worked for a short while on Saturday after the engineer replaced the presure switch but it crapped out again after 4 hours. And again yesterday he got it going having replaced what looked like an electrical connector, but it failed to come back on again this morning with the timer, nor after turning the boiler off and resetting it.
TK
October 2006