for safety reasons you should get it checked out ASAP and not just live with it - could be a part thats not working properly and affecting perfomance of bioler (should be making that loud a niose especially after 2 years) and IF the performance of the bioler is affected this affected your CO levels generated by bioler Again it may be something simple but better to be safe than sorry Whatever you do dont touch bioler yourself
max
November 2009