The last paragraph of page 8 of the GARN installation manual refers to a vacuum relief duct (shown on drawing A-1 on page 6). I can, for the life of me not figure out why this is required. Could someone please enlighten me? The manual states,
"Because the GARN WHS unit utilizes an induced draft combustion blower a vacuum relief duct is required. Thus a vertical 4"x14" sheet metal duct is installed along the north wall within the insulation. The outdoor portion consists of a screened weather hood positioned 36" above grade. The top of the duct is open-ended and terminates above the insulation that surrounds the GARN unit. The upper end may also be screened. No damper is required."
In the diagram, this vent is shown by the tank and does not come out in the portion of the building containing the blower. In my GARN barn, the ceiling is open between the GARN unit and the area in front of the unit. Does it matter where this duct is located? And again, what does this duct do anyway?
Paul
"Because the GARN WHS unit utilizes an induced draft combustion blower a vacuum relief duct is required. Thus a vertical 4"x14" sheet metal duct is installed along the north wall within the insulation. The outdoor portion consists of a screened weather hood positioned 36" above grade. The top of the duct is open-ended and terminates above the insulation that surrounds the GARN unit. The upper end may also be screened. No damper is required."
In the diagram, this vent is shown by the tank and does not come out in the portion of the building containing the blower. In my GARN barn, the ceiling is open between the GARN unit and the area in front of the unit. Does it matter where this duct is located? And again, what does this duct do anyway?
Paul