hey guys, i need some help with sizing an exhuast fan for a hood.

first of all the hood is approximately 5' by 14'. their is a 3' broiler a 3' oven/griddle and 2 fryers. all gas.

the problem is the exhaust fan on the roof has very little info on it.

when i looked in the hood control compartment the most i can tell is the fan should be no more than 1.5 hp and i know its 3 phase 230 volt. (this is according to the schematic)

on the roof the fan has a 2hp motor that is 3 phase. it is rated at 6.7 amps but is drawing 2.6, so its obviously oversized or has the wrong pulleys or something. anyway on fan i can read
stk no 723
1/3 hp

i know that the wheel diameter is approx 14" and 7" deep.
the curb is 24" by 24"

so ive got a general mess. but what i want to know is... what is the correct way to size the fan? the customer is having problems with smoke roll out from the broiler. and the fan is going to need to be rebuilt due to worn bearings and shaft. i figured rather than rebuild this thing i might be better off to put in a fan that is sized correctly to handle the broiler..

i hope this makes sense.

im going to look over my code books now.... just wanted to see what the real brains thought!!