Alpha he 33 airflow problem,

[kris]

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 ,,,,,,

 

[ShaunCorbs]

Have you tested the air flow with a manometer?

 

[kris]

No Shaun I only had couple screwdrivers as left my tools at another job, but I couldn't see any test points anyway , certainly not out with the chamber,

 

[GH77]

This might sound stupid, but have you checked the flue terminal? ... i had a similar fault once and the customer had removed an internal door, taken it outside and leant it against the wall inadvertently blocking off the flue, boiler would run with the case off... agree with Shaun about manometer, there should be a reading printed on the aps ... I'd connect a digital manometer to the fan to see what it's producing

 

[ShaunCorbs]

No Shaun I only had couple screwdrivers as left my tools at another job, but I couldn't see any test points anyway , certainly not out with the chamber,

pull the tube off the aps and see what the readings do when you remove the cover

 

[kris]

Yeh I checked the flue , if you read my text I had the whole flue removed to check integrity , simply slacking one screw on the chamber cover allows the switch to prove and fire up,
GH77 you can't attatch a manometer to the fan as no test points , this boiler isn't a Venturi type rather it's a snorkel pipe attaching the APS to the chamber and only test that you could do would be to attatch to that with door off , but I can't test with door on

 

[ShaunCorbs]

couldnt you put a tube on it and pop it through the air intake port and gaffa tape air test port up temp ?

 

[kris]

http://www.alpha-innovation.co.uk/c... models/HE 25-33 Inst & Serv Inst 19-3-08.pdf

The only part that I haven't opened up is the condensing heat exchanger which is what the fan is attatched to ,

 

[kris]

couldnt you put a tube on it and pop it through the air intake port and gaffa tape air test port up temp ?

Possibly Shaun Cheers for your input mate it's much appreciated, I even called alpha technical and didn't think much of the help,

 

[GH77]

Blocked recuperator?

 

[ShaunCorbs]

Possibly Shaun Cheers for your input mate it's much appreciated, I even called alpha technical and didn't think much of the help,

there useless theve gone worse

@Alpha man any help mate?

 

[kris]

Blocked recuperator?

Possibly , that's only bit I ain't stripped down,

 

[Scott_D]

Split tube to APS?

 

[kris]

Split tube to APS?

No all the tubes are fine and clear Scott,

 

[jtsplumbing]

May just be that the fan is running to slow !

 

[Alpha man]

Replied.

 

[king of pipes]

What was the outcome on this one kris did it get sorted ? Kop

 

[masons]

Replied.

share and share alike

 

[Gary80gas]

The manufacturer should be able to give you the air pressure reading the aps needs to operate, could be a fraction out. Then read ohms on fan, could be slowing down.

 

[Alpha man]

The manufacturer should be able to give you the air pressure reading the aps needs to operate, could be a fraction out. Then read ohms on fan, could be slowing down.

You'll be lucky, change the Red APS and clean the fan Venturi and tube.