reducing hood exhaust system noise????

[brewchef]

Wife and I are building a small pub with an open kitchen. The hood system was installed last week, the fan is directly opposite the wall the hood was mounted to so the length of pipe to the fan is like a foot. The noise from the fan is louder than I hoped and really makes the pub noisy.

Next year we may mount the fan further away from the hood itself. The difference in price between mounting the way we did and going up to the roof was like $10k-$15k more and we just couldn't afford that right away.

I'd like to know if it's possible to adjust the speed during quieter times in the pub to reduce the noise output. Perhaps a "dimmer" style speed adjustment or a variable speed switch. I think we have a lot more suction than we need anyway, and a "dimmer" could dial-in the appropriate suction and reduce the noise. We have make-up air too. Obviously this would have to be adjustable too.

[keepyoucool2003]

You should inquire to the contractor that installed your system to see if it was balanced, or if balancing was even included with the cost. If it wasn't balanced you should consult a CERTIFIED air balance contractor to address your questions. Any contractor can throw a hood system in without balancing it, you may end up with a system that is moving too much/too little air, or two systems that are not working together

[rayr]

2 speed motor

[maninblack]

The system should be balanced to the minimum allowable cfm per linear foot of hood. This will also minimize the building HVAC load by lowering the cfm required for makeup air. An air balance company will be able to assist with this.

[mgs2253]

Check out Melink intelli-hood controls. When hood turned on fan goes to preset minimum speed of 10-50%. When smoke and/or heat is detected fan speeds up to maintain exhaust air temp. Payback is usually 1-3 years on install but should still be less than cost to move fan that would save zero on run cost.

[RafterRat]

It's quite possible that the fan can be slowed way down being that the duct run is so short. You are probably over-exhausting quite a bit. How is smoke capture?

I would contact a certified air balance company Melink Corporation (http://www.melinkcorp.com) and have them perform a full store test and balance. You could be spending thousands of dollars in wasted energy from unbalanced equipment. As well as just having an overall uncomfortable atmosphere due to noisy or drafty equipment.

Good luck with the Pub :D

[powerup]

Check in your area who is very good with air flow issues and has a proven tract record with restaurants in your area. Well worth the money. Will save you plenty. Not to mention less headaches. Best of luck to you.