Baxi duotec rumbling

[Steve]

Every so often my Baxi duotec 28 GA will ignite, then just before it "revs up" it will start rumbling (no louder than the normal noises is makes) and the flame will extinguish, followed by the "whooshing" sound which is normal, sounds like it is cooling something inside the boiler.

30 seconds or so later the ignition process resumes and it revs up as normal, but the rumbling is a bit worrying. Is this normal?

 

[Groovejet]

Dont quote me on this!
But i had the same problem on 2 Baxi 40 he duo tech's, my mams house and my friends.

They described similar noises as yourself and also some quite worrying knocking?
What i've been told is that the HW plate heat exchanger is used as a system by-pass and the problems are arising from here.

Bad design??

Full of dirt?? And nowhere to go??

Dont really know ins and outs , but thats part of a storey i was told, is it correct well thats another matter!!

 

[Gas2Air]

Dont quote me on this!
But i had the same problem on 2 Baxi 40 he duo tech's, my mams house and my friends.

They described similar noises as yourself and also some quite worrying knocking?
What i've been told is that the HW plate heat exchanger is used as a system by-pass and the problems are arising from here.

Bad design??

Full of dirt?? And nowhere to go??

Dont really know ins and outs , but thats part of a storey i was told, is it correct well thats another matter!!

The plate isn't used as a bypass.

 

[muggles]

Sounds like a poor gas/air mixture to me, get an RGI in to look at it

 

[gas112]

gas2 air groovejet is right on the duotecHEa the plate IS a bypass.

Steve call Baxi out to have a look they will reset the mixture for you if req your boiler will still be under g`tee