Basic boiler crackling sound

[Claudia Everest]

I had a Baxi boiler fitted in February and when it is running it makes a weird crackling sound. I feel like it is in the pipes that exit and enter the top of boiler. It doesn’t always crackle, I think it is more when it is starting up. Is this normal? In every other respect the boiler seems to work fine. Am I just being a worry wort?

 

[Mottie]

Sounds like pipe expansion noise possibly?