boiler noise

[ChippieBrian]

Hi, I have read some of the posts on boiler noise and just need clarification please. My chaffoteaux boiler starts up in the morning and I can hear the normal hum which is fine, then after about 30 seconds the aeroplane noise starts, it is very loud at first then after about 1 minute it drops down, then comes back in waves, slowly diminishing untill after about 5 minutes it stops. It also does the same when the HW it turned on.
I'm guessing it's the heat exchanger! I have put cleaner in the system for 3 weeks as per instruction, cleaned out and re filled with noise reducer and inhibitor but it's still there, some days not so bad but some days really loud.
Any advice please?

 

[ChippieBrian]

On closer inspection it seems boiler has a 2 stage burner. When on the low burner there is no noise but when the second stage kicks in it gets noisy and as it gets hotter it fades out as the second stage is not needed.
Any clues?

 

[gas4you]

What you are describing is the boiler modulating.

If it is noisey on full power I would suggest getting a RGI in to check/service it.

 

[eyespy999]

Hi there

My boiler has the same symptoms as the ones you have described re the aeroplane noise, it is the same brand of boiler too. I have a sentinel product circulating that i put in yesterday. I have also cleaned the central heating filter as it was fouled with debris.

It is slightly quieter but at 5am i do not need an alrm clock as the bolier wakes me!

Did you manage to resolve you problem if so what was it?

Thanks

Lee