I have a Halstead Best 60 boiler which is less than two year's old and
has suddenly stopped functioning. Initial investigations showed that
the 2A inline fuse had blown. Replacing this has got the pump going
again but the boiler still fails at the first hurdle i.e. the fan does
does not start. Working throught the troubleshooting chart in the
manual, I got to the point where pin 1 of the ignition control
connector was not showing 10vdc. On the strength of this, I have
replaced the thermistor and Aquastat PCB but am now no further
forward. The connector still shows only 2vdc when the connector is
disconnected and 0vdc when connected.

I am now confused. Either the replacement PCB is also faulty or the
problem actually lies in the ignition assembly PCB, the only other
likely, major (and expensive) component left. I might also mention
that the ignition lockout light started coming on regularly during the
summer but seemed to settle down again in the colder weather. Does
anyone have experience with this type of boiler please.