I've got a Baxi 133HE Plus boiler and have been recently experiencing ignition issues, in the main the boiler starts up fine although on the odd occasion it will fail to ignite and requires a reset.
The main problem is the noise however, sometimes there will be a fairly loud bang when the boiler ignites, I've had British Gas out several times and they still can't get to the bottom of the problem despite changing several parts out (thankfully under the insurance cover).
You don't say how old the boiler is, but I would guess that it's quite new, if so contact Baxi Service, they have their own team of engineers and there may be a modification for the combustion system on this boiler?
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