worcester 28cdi ignition fault

[postscript]

This boiler lights perfectly on hot water or central heating demand but the spark continues and the boiler locks out. The manual, after carrying out continuity and position checks for the flame sensor, says replace the circuit board. I have access to an identical boiler and have fitted the complete electrical panel to the faulty boiler to no avail. I have also swapped the burner complete with flame sensor without success. The flame looks fine and adjustments to the start up pressure makes no difference. Everything put back on the other boiler works perfectly. Help.

 

[Dan Robinson]

What does your RGI say about all this?

 

[postscript]

I am a retired gas installer and, while no longer registered, consider myself competent to do my own service and repairs. Have carried out fault finding on boilers for years but have never come across this problem, hence the question.

 

[Andygasman2010]

There's a separate forum for registered and retired RGIs called The Combustion Chamber. If you send website admin your details they can give you access.

You won't get much gas related advice in this public forum for obvious reasons.

In the meantime, check polarity.

 

[picasso]

poor earth connection ?

 

[simond]

Sounds like polarity of supply to me, too.

 

[postscript]

Thanks to everyone who replied to my query with the 28cdi and particularly the forum tip. Polarity and earthing were all fine the problem was with the contact between the multi plug and the board despite continuity in the sensor cable.