Apollo 30/50B Noisy Boiler

Help - boiler emits sound like electrical arcing or the winding up of a clockwork toy when burner ignites or switches off. Boiler continues to work effectively but sound disconcerting and affects the CD player in different room. Fault is intermitent and seems to appear when boiler has been on for a significant period of time.

Stat or gas valve, get it checked out by a pro.

suppressor across the gas valve solenoid is us needs replacing think its a diode ask the sparks

I went to the same problem last week, the gas valve is modulating it alters the gas pressure to the burner, when the boiler gets up to temp the flame starts to drop does the noise start

lower the stat on the heating side after the boiler is hot when you lower the stat does the noise start ??

these simple tests will tell you the gas valve is on the way out

But dont start messing with the valve get corgi out..!

The valve i changed cost £85 and i charged £60 to change it

Hope this helps