Hey guys long time no type , I've been busy busy this last while and I've a wee issue if anyone can help,,,, I was called out to a boiler breakdown no heating or hw, now after a bit of diagnosing I've found that basically the APS isn't proving, now I've done all my checks that when it does prove everything works as should, there was 24v going to aps but simply not making the switch , so I started to look at causes and it's one of those that slacken a screw on combustion door she fires up no probs so she's being starved of airflow, but here's where I'm getting bit stuck as I basically totally removed the horizontal flue and elbow and all seemed fine, I removed the fan and cleaned out impellers checking no dents etc and rewired the fan back up in the palm of my hand away from boiler and it blows a treat, I removed the air tube and snorkel and made sure all was clear ,,,now this boiler like mentioned is an Alpha he 33 with the combustion heat exchanger attatched to the fan, all seals seem ok , the only bit I haven't went into the guts of is the combustion heat exchanger, when I removed the flue bend and looked into the boiler from above there was a load of silt lying in combustion heat exchanger that I hoovered out , I'm just wondering if anybody has had this problem with this model of boiler , I mean normally a aps problem on boilers are simple enough but this one is being a booger, and also to say there's a brand new APS fitted so it's not that , the flue seems to be fine , also seals are fine ,, Any ideas gents ,,,,,,
