Potterton Netaheat 50e re-igniting

[Thecasementkid]

I've an issue with my faithful old Potterton 50e boiler. It works well I've had few problems during its 18 years life.
Suddenly however, an issue has arisen. When it's fired up, a relay inside intermittently clicks and it tries to re-light itself, even though its already alight. It's like the boiler is "hiccuping" if that makes any sense?? When I look through the inspection glass, it looks like it switches off very quickly but restarts in an instant.

I'm obviously not going to mess about with it myself, but would like some thoughts if any boiler experts on here have experienced anything similar. It doesn't happen all the time, just occasionally.

 

[twgas]

most likely culprit is the pcb.

 

[Gasman28]

+ 1

 

[Ihavenojob]

Check the gas meter handle hasn't been partially turned off,low gas pressure can cause these symptons.