keep getting f1/f4/13 whats it mean got no manual had to engineers round still same ,can you tell me whay it means ,(codes)

peter, November 2012

F1 is Failed ignition sequence
check condensate drain is not blocked
check gas valve operation
check fan starts
F4 is Lost flame during running
Check gas pressure at inlet
check electrode
check flue.
F13 not a clue

Phone 0844 7360059 between 0830-1800
its their tech advice line

I'm phoning them tomorrow as my boiler is over pressurising when the heating is on!

Andrew, November 2012