Remeha quinta 65 making very loud bang on start

[bright spark]

I called to a job this morning. A customer had 2 remeha quinta 65's broken down with separate faults. The first had very low ionisation electrode readings. Changed the electrode and everything worked fine.
The second boiler was totally different. When the boiler went through its starting sequence at stage '2' a very loud bang came from the boiler and it went to lock out.
I had loads of breakdowns on my plate so I told the customer that I would return on Monday to strip it down. I was wondering did anyone else encounter this problem and how did they solve it

 

[IDCHAPPY]

2 is ignition, I presume you are Gas Safe Registered?

 

[bright spark]

Yes I am gas safe registered (RGI) in ireland. As soon as the boiler goes to ignition a very loud bang comes from it. It's as though the gas valve may be passing and the boilers 'chamber' has filled with gas.

 

[IDCHAPPY]

What error code is it giving? Just ignition failure?

 

[bright spark]

It's giving '02' code. With the noise you'd think the boiler was nearly going to jump off the wall. Anyway roll on Monday morning.

 

[bright spark]

Anyway I haven't been on the site in quite a while, is there any gas commercial forum I could sign up to. I have my RGI details that I could submit. I am mainly involved in commercial gas work in Ireland.

 

[Billy Bob Bob]

bright spark send me a picture of your rgi card we can put you in the gsr/rgi only forum then and you will get a lot more advice until you do that your gas related posts will be closed