Just a note to mention that I received a reply from my MP the other day to my recent letter about data sharing. He gave me a thorough reply, pointing out several benefits of responsible data-sharing (reducing red tape and cutting bureaucracy by permitting departments to share information). The thing is that I don't have any problem with responsible data-sharing. It's the risk of irresponsible stuff that worries me...

At risk of turning into a boiler specialist, I wanted to share some useful info provided to me by John B. He has a Potterton 16/22 Netaheat Electronic LPG boiler and had similar symptoms to my dodgy old boiler. His fan and pilot ignition were OK. However, the ignitor was clicking every second up to two minutes plus before the main burner cut in when starting from cold. When hot, it only took 2-3 seconds for the burner to light. He'd replaced both the electrode and the thermostat to no avail.

Unlike my boiler though, his had a different PCB, a Potterton 407676 (the reverse side of the PCB also shows the number 90911/4). What seemed conclusive to me of an electrolytic capacitor problem was that a gentle tap (when cold) on the PCB triggered the main burner. John kindly took some photos and provided technical details of his PCB for me to post.

The original electrolytic capacitors were marked as follows:

C9: 220uF, 16V/85°C
C5: 100uF, 40V/85°C
C4: 22uF, 50V/105°C

John replaced them with capacitors rated to cope with slightly higher voltages (Maplin part nos. VH42U, VH39N, DT57M respectively). His boiler now works perfectly again!

If this is helpful to you please leave a comment, and link if you can, to make it more likely to be picked up by search engines for other people. If it's saved you the cost of a replacement boiler and you'd like to express your thanks with a donation (secured by PayPal) to support my hosting costs, it'd be very welcome. I'll donate 50% of your contributions to National Energy Action, the UK's leading fuel poverty charity, campaigning for warmer homes - it seems like an appropriate cause.

Disclaimer: Don't electrocute or incinerate yourself. This page is for information only. Landlords and employers are legally obliged to use a registered CH engineer for all gas work. I accept no responsibility for any accidents or problems.