Posted by jtown on January 01, 2000 at 19:26:06:
In Reply to: Re: Knocking inside gas fired boiler posted by Dennis Rockefeller on January 01, 2000 at 17:58:27:
Blowing down a boiler is to just drain the sediment laden water off the bottom or a surface blow on big boilers to skim the water line of floaters. A lot of people here say flushing which to me would mean flooding the thing with lots of water to clean it, like eyes, car radiators or toilets. Anyways, You might have expansion noise of the burners expanding or the boiler castings themselves. Check that burners are free, They might need lifting out and the firebox vacuumed good. The inside end lifts up and they come off the gas spuds and then you slide them out and clean where they sit. Make sure they go back right, do one at a time if you need to. Don't mess with the air shutter if there is one. The burners usually should sit in there loosely to allow expansion. Try the screwdriver stethescope trick to try to isolate it and fire it with any inspection covers off that you can to use it on the casting etc. Check that draft hood etc is just snugged down onto gaskets. Anything that might want to grow slower than the part that it is clamped to.