Im new to the site....Last evening I was sleeping so well and all of a sudden BANG...like a small caliber gun...even set off the glass breakage system of our security alarm...couldnt find anything all over the house and all we could come to reason it was the heater...Now I think back on it and yesterday evening as I was starting a fire...my heater seemed to groan and stretch even more than usual with a new fire...then this evening my heater makes almost a constatnt slow....click click po...tink clank pop. click,,,etc etc but then it will stop and be silent...then it may resume its complaining....I have a cracked refractory shoe that I am waiting to arrive...but I have continued burning my heater....has anyone else ever experienced this horribe sound coming from their heater? Ours is a vermont castings defiant noncat......Please help if anyone has any suggestions