This morning I had a call at a new restaurant that we installed the RTU's on. The call was the restaurant was filling up with smoke the previous day when they were test running the grill. So I arrive this morning and check the exhaust hood only pulling 3.2A motor rated at something like 5.4-6.0A FLA. I spun the drive pulley all the way closed and then backed it out one turn and got the motor to pull 4.6A. Checked the make-up air unit pulling close to FLA. Made sure they were both spinning in the right direction--they were. Then I noticed 2 of the RTU,s our company installed did not have fresh air on them. Thought maybe they were inside the 10' perimeter of the exhaust--nope. Go get fresh air vents (manual) and install them. I set all three fresh air vents at 50% dont remember the exact dimensions. Go back down in the kitchen and they were starting to cook chicken--perfect--now I can see if the exhaust is doing a better job--pulling smoke out great. Later that day get a call-back kitchen was full of smoke again--Service Manager took the call. Asked him what the problem was and he said when he got there the smoke had already cleared out but he went ahead and spun the pulley down that last turn and got the motor to pull 5A. I still don't think this will help--guess we'll find out tomorrow. I am an ac tech and don't have really any experience with this. The building seemed to be slightly positive when I left. Any input would be greatly appreciated on this. The RTU's are Lennox--2-4 ton units and one 5 ton. M/N-CHA16-060-1P and the 4 tons are both M/N-CHA16-048-1P. The make up air is supplying 1400 cfm and the exhaust is rated at 1750 cfm.