Ravenheat CSI Primary - Condensate blockage

[spamface]

Hi, I fitted my own Ravenheat CSI Primary boiler around 8 years ago. I'm aware of the controversy surrounding DIY work.
The only trouble I've previously had from the boiler was a few months back when the pilot pipe finally became blocked with soot. However I've now run up against a more formidable problem. The condensing heat exchanger has become blocked with aluminium oxide deposits, resulting in water dripping from the fan joint and finding its way out of the combustion chamber via the ignition lead to the electrics. Bad news....
Has anyone had any experience with removing aluminium oxide from this particular boiler? They haven't made it easy. The trap seems clean, the deposits are certainly visible in the exchanger and blowing into the condensate pipe allows it to drain temporarily, though it appears the oxide just flows back and blocks it again very quickly.
Thanks.

 

[Slugbabydotcom]

Can you clarify the blowing back up the condensate part of your story. Did you blow from the end of the condensate line or remove the condensate pipe and blow up the hose on the boiler itself. It's more usual for the line to be blocked between the boiler and the drain than there to be a blockage inside the boiler.

If you've seen that the condensing heat exchanger has got aluminium oxide in it then you must have removed the fan to do that.
I would disconnect the condensate from the drain and run the rubber tube to a bucket. Then pour some water through the condensing unit. If it backs up badly then you could try taking the trap off [usually very difficult] and getting some wire up the back, or as I would prefer take the boiler off the wall and strip and clean it on a bench.