Rust in vapor fire firebox

[Micdrew]

Hello again, I recently got a stainless steel liner kit for my kuuma VF firebox, in order to install it I had to take the brick out, when I removed the floor brick I noticed at the back of the fire box, more so in the corners there was a lot of rust that had formed and when I took the scraper the steel pealed away, at the end of the season I removed the smoke pipe and cleaned the furnace. I have a dehumidifier 10ft for the furnace and a heat pump water heater in the basement so it stays pretty dry down there, where would this moister be coming from? My thought is when the ac comes on the cold air is coming in contact with slightly warmer steel? Im thinking I should disconnect the ducting and cap it after the heating season next year?

 

[Dan Freeman]

I have a steel stove. My chimney sweep told me after he cleaned my stove at the end of last season to put an open box or bowl of baking soda in the stove to absorb moisture until the next season. Baking soda is a good moisture absorber. There are also other things you can use.

 

[JMihevic]

I have a Tarm MB55 Solo Wood Boiler that has a coating of creosote that is very difficult to remove. Creosote is very corrosive and can rust the boiler steel walls if moisture is present. When my boiler is not in operation, I put a 60 Watt resistor mounted on a 10" X 12" aluminum plate. That raises the boiler temp about 5 degrees F above the ambient room temperature. In this way the air inside my boiler is always above the dewpoint temperature. If I scrape any random spot on the boiler walls, down to the steel plate, it is bright and shiny. I installed my boiler in 1980, have used it every winter for 42 years with no problems.

John M.

I have a flapper damper in the pipe to the chimney which I close to minimize air flow through the boiler when it is not in operation.