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determining amount of CFM needed
i realize that i need to pull additional air into my boiler room for several boilers that i have in it ,through the flexible 5 inch duct that is in place. my question is how do i determine how much air and how strong the fan must be ( is there a formula and is it based purely on BTU or does thenumber of boilers also play a role ) ? also can someone recommend an online resource for purchasing such a fan. thankyou for your assistance