Re: Backdraft - Negative Air Pressure
Has this always been the case or is this something that just started hapening ? Has anything been done or changed within the home ?
Originally Posted by rzxspz
In many jurisdictions the mechanical codes require a fresh air supply from outside to inside for combustion equipment. Usually a minimum 6 inch duct is required to bring in enough make up fresh air into the space for fuel fired furnaces , boilers , water heaters are located. Generally this was implemented for those appliances that were not direct vented and relied on the air within the home for combustion and vented out common type of flue.
Depending on your local requirement that 6 inch duct can simply dump cold air into the space ( about a foot off the floor ) -- or --- they can drop into a 5 gallon bucket --- or --- they can be tied into the cold air return plenum at a furnace.
In your case it sounds as though you have a direct vented ( intake combustion and exhaust ) so the requirment for the make up air duct for the furnace isn't required --- but --- you have a fuel fired water heater and a fireplace that are having back drafting issues.
I recommend getting a professional HVAC or chimney/fireplace spe******t or even an energy auditor to determine what the cause is for the negative pressure issue.
There are a myriad of things that can cause this issue --- from wind pressure --- partially insulated and sealed parts in the home --- flue issues --- etc
"" an ounce of perception -- a pound of obscure "