Baxi Barcelona whistles

[Jeronimo]

Baxi Barcelona system boiler, 5 years old.

Problem: it produces a loud whistle (even howl) during parts of the firing, usually as it is modulating down. Lasts for maybe 5-10 seconds as the fan slows.

I have recently replaced the combustion box door seal and tightened the screws securing the top and bottom covers. Baxi has advised it is the o-ring type seals in the combustion box top and bottom covers need replacing. (Heat exchanger out )

Tightening 7 of the 8 screws (can't get anything onto the one under the flue) did not alter the whistle but did stop the casing shake when the boiler lights up.

Another call to Baxi advised it might be the burner assembly (130 + VAT!! )

Any ideas on the cause of this which caused my brothers dog to howl in sympathy all night when they visited recently

Thanks, Jerry

 

[punchjoshua]

have you checked the thimble inside the boiler to see if it is gunked up,
i have a baxi that would make a whooping noise every now and then the thimble was clogged up with s_ _t making the water strain through thus making a whooping/whistling sound.

 

[Jeronimo]

Thank you for the response Joshua. I only just got round to checking for it

Thimble? I am not familiar with this term wrt this boiler. Please enlarge on what you are referring to.

Sounds like something in the condensed water discharge system. I have not investigated the water trap but think it is clear.

Appreciate your further explanation.

Jerry

 

[Gert_Lush]

I had a Baxi Barcelona and mine made a similar whistle to what you describe.
Mine turned out to be the bearings on the fan, which when replaced (£80+vat) cured it. No more early morning wake up calls when the boiler fires up!
(Smug bit... I'm not a boiler engineer, but i know what knackered bearings do and what they sound like. I told the boiler engineer this and he tried similar fixes as you have done, and to no avail. Thankfully i was right, but it cost me over £100 for the privilege!)


Hope this helps.

 

[Jeronimo]

Thanks Gert,

I think it is not the fan. I have listened to it by pressing a screwdriver on and sticking my ear to the handle (without using glue ) Was quiet. Also took the fan apart and checked the fit. No rubbing of the impellor or play in bearings.

However, the noise now seems to have gone away to be replaced with condensation dripping out. Perhaps the outlet is restricted as mentioned by Joshua above.

I will try to remove the bottom cover of the combustion box to check.

Cheers, Jerry

 

[Jeronimo]

I checked out the condensation dripping from the boiler.

I found that the bottom cover of the combustion box was loose once again. The condensate trap was full so I emptied that and checked there is no blockage out of the combustion box. That was clear.

I refit the combustion box bottom screws with locking washers and also on the front cover and screwed it all up tight.

Because the boiler had been off for a while (too hot to handle otherwise ) when i restarted it, the flame modulated to a condition producing a continuous load whistle, more like a whine

I determined this was coming from the front cover of the combustion box which was vibrating strongly like a speaker cone. No amount of pushing on it attenuated the sound.

Any ideas

Jerry