We intermittently get an eggy/sewer smell from the boiler cupboard. Had numerous gas tests carried out and no gas been detected/no carbon monoxide.
Recently been advised that this could be a loss fitting on the condensate pipe which is bringing up sewer type smells back into the flat as it will be connected to a larger waste pipe further down the system.
I think this must be the issue but what I don’t understand is why it is intermittent and why it has got less of an issue now we’ve been using the boiler less with it getting warmer. Does the boiler fire up and then swish the condensate pipe or something, which would have made the smell more regular in winter? Thanks in advance if anyone has any comment!