Have just started using a 3 1/2 inch MAC Steam Boiler, it came with the new addition to the fleet, a TiD Steam Tug. I have noticed that it howls/whistles quite loudly, but not all the time. The boiler is fitted with a metal gauze burner and a No8 gas jet - I also have a ceramic burner to fit the boiler, but believe the mesh boiler was put in as an upgrade - have you any suggestions on the cause and or remedy for the loud howling/whistling?