We recently had a new en-suite fitted. Since a heating engineer came to fit the pipe work for the bathroom radiator, we have had a strong musty /foisty smell coming from the airing cupboard. It is now making the hallway smell too. Not sure if it’s coincidence but wondered if there is anyway this could be caused by the system being emptied to install the new radiator, or if it could be anything else. We have checked all of the pipe work in the cupboard and nothing appears to be leaking. Both the boiler and hot water tank are in the cupboard.