Fpm ?
- Thread starter aph111
- Start date
I got a customer that has a 12 foot vent hood .. Duct is 12x24 .. When he moved into this restaurant he said there was no fan on the roof and wondered if I would take the one off his old restaurant and put it on the roof curb at his new location.. I said Sure..
I brought a 5 hp -3 phase fan from his old building and mounted on the roof curb , we got it all hooked up and turned it on.. Man did that thing suck.. We heard aloud crash from up front..It was his front Glass Door Close.. The fan pulled so much pressure in that small building it slammed the door so hard it broke out the glass..
That was 6 months ago .. Since then I have been out there 3 times to remove napkins, rags, plastic plates and even a baseball cap from the exhaust fan..
Balance is essential for correct vent hood operation ..
As a rule of thumb if you turn both the retun air and exhaust on , open the kitchen door just a little bit .. It should not blow open or shut..
If it does most exhaust fans and return air fans are made with adjustable pulleys on the fan shafts.. Adjust then in for more speed and out for less speed.
I brought a 5 hp -3 phase fan from his old building and mounted on the roof curb , we got it all hooked up and turned it on.. Man did that thing suck.. We heard aloud crash from up front..It was his front Glass Door Close.. The fan pulled so much pressure in that small building it slammed the door so hard it broke out the glass..
That was 6 months ago .. Since then I have been out there 3 times to remove napkins, rags, plastic plates and even a baseball cap from the exhaust fan..
Balance is essential for correct vent hood operation ..
As a rule of thumb if you turn both the retun air and exhaust on , open the kitchen door just a little bit .. It should not blow open or shut..
If it does most exhaust fans and return air fans are made with adjustable pulleys on the fan shafts.. Adjust then in for more speed and out for less speed.
Douglas Hicks
Member
CFM is a function of duct size, number of bends in the duct and fan size, fan speed.
Start w/the size of the hood, appliances, gas or electric, that gives the CFM, add the static pressure and there you have the CFM requirments! Easy as pie. If I remember, tomorrow I will get my book out of the Sprinter and post the formula
Douglas Hicks
General Fire Equipement Co of Eastern Oregon, Inc
Start w/the size of the hood, appliances, gas or electric, that gives the CFM, add the static pressure and there you have the CFM requirments! Easy as pie. If I remember, tomorrow I will get my book out of the Sprinter and post the formula
Douglas Hicks
General Fire Equipement Co of Eastern Oregon, Inc