|reply to misiek |
Re: External air supply for an 80% AFUE furnace?
When I replaced our furnace in Denver the building code required two fresh air sources to the furnace room, one high and one low, to pass inspection. The furnace installer told me after everything was done and inspected I could shove a rag in the high and put a coffee can under the low to slow down the cold air. The low had to be within an inch or two from the floor so he put on a piece of pipe at the bottom that I could take off, put the coffee can in place and reinstall. When the furnace was off this would stop the low from drafting air and when the furnace was on would allow fresh air to enter through the low due to the turbulation caused by the furnace. I was kind of doubtful but it did work, never felt a draft out of the furnace room. The weight of the cold air in the coffee can was sufficient to stop any draft up into the warmer air above the top of the coffee can.