In message , SteveJakab
writes

Hi,

I have an old Potterton Netaheat boiler, which was working fine until
recently. Now it doesn't spark all the time. Even if the gap between
the electrode and metal grate is very small, it won't spark
consistently. If the gap is too small, it won't light the pilot light.
Do you know if this is a 1) eletrode/HT cable problem, 2) Spark
generator problem or what else it may be. The unit is earthed well.

Also, so that I can order new parts, how do I find out if it's a Mk1 or
Mk2 unit? Any identifying things to look out for?


Sounds like either the HT cable is shorting to the case or breakdown in
the HT transformer on the pcb

The older Netaheats have a spark generator, the later ones a sequence
pcb (407676)


my site www.cetltd.com may be of use



--
geoff