Foodservice Equipment Reports

Checking Under The Hood

Wayne Stoutner knows firsthand the value of proper exhaust hood maintenance. Several years ago the golf club he belongs to burned down as a result of a grease fire in exhaust ducts. Fortunately, no one was hurt, and just as fortunately,
the club wasn’t a client of Stoutner’s company, Appliance Installation & Service Corp. of Victor, N.Y.

As president of AIS, Stoutner says the most common maintenance problems he encounters with hoods are clogged grease filters and poorly designed exhaust systems that result in inadequate capture and containment of cooking effluent. In both cases, he says, the kitchen staff all too often pulls the grease filters out of the hood entirely, which lets the grease in the exhaust coat the ductwork
and fans and create perfect conditions for a grease fire.

“Isn’t that what a fire suppression system is for?” you may ask, if only tongue-in-cheek. Fire suppression systems are designed to put out fires on the cooking line. They’re no good, though, for fires in the ductwork. If there’s no grease in the ducts, fire is far less likely to spread.

Another common exhaust system failure? Broken fan belts. “A $5 belt break can shut a place down instantly,” Stoutner says. “Belts should be changed at least once a year, even if they’re designed to last longer.”

Three-Pronged Maintenance
Your approach to exhaust hood maintenance should encompass three areas, Stoutner says: fire suppression, ductwork and the exhaust system itself, which includes not only the hood but any makeup air system.

If you cook anything more than toast, you need an exhaust hood, and in most cases that means you need a fire suppression system. That’s in most local building codes, which also require annual inspections of the system. NFPA 96, a guideline that some but not all municipalities adopt, calls for quarterly inspections of high-volume operations and those doing wok cooking or charbroiling, and semiannual inspections of operations doing only moderate cooking.

Your ductwork also must meet building code, and it should be cleaned semiannually. While you’re thinking of your annual (or more frequent) fire suppression system inspection, you might as well schedule duct cleaning, too.
At the same time, you should hire a good service company to take care of everything else. What does that entail? At least twice a year, your service technician should:

• Clean fan blades. If your grease filters are doing their job, your fans should be pretty clean. If not, your service tech will clean the fan and find out why it’s dirty.

• Check grease fittings. Blower wheels and shafts may need lubrication.

• Check belts. Belts should be checked/adjusted during the service tech’s regular semiannual visit and changed once a year.

• Inspect ductwork. A good service tech also will check to see whether the ducts have been cleaned properly.

• Check filters. The makeup air unit’s filters should be cleaned or changed twice yearly to make sure your kitchen is getting the airflow it needs.

“Building codes have changed to [include] heat and smoke sensors in hoods, which automatically turn fans on and off as needed,” Stoutner says. “If your system has these more sophisticated features, your service tech also will have to check these sensors and controls.”

What You Can Do
So that’s the rundown on what a service tech should be doing for you. But you and your staff can help maintain clean hoods in between service calls by doing the following:

• Clean your grease filters. Some grease filters require daily cleaning. Standard filters should be cleaned at least weekly, or more often if you’re cooking high volumes of fried, charbroiled or griddled foods. Follow the manufacturer’s recommendations, which may or may not include running your filters through the dishmachine.

For tough cleaning problems, let filters soak in a pot sink of hot diluted degreaser solution (mixed per manufacturer’s instructions) and let stand for several hours. Steam cleaning may also work well.

• Clean hood interior. Any time you clean the grease filters, clean the interior of the hood at the same time, whether daily or weekly.

• Empty/clean grease cups or drains. Same goes for grease drains—clean them whenever you clean the filters and the hood.

The cleaner your exhaust hood, the less maintenance it will require, and you’ll reduce the chances of a damaging fire.

And if you notice a problem with smoke or heat in your kitchen after thoroughly cleaning your filters and hood, call your service tech to help troubleshoot the exhaust system from the makeup air unit to hood design.

FER thanks the Commercial Food Equipment Service Association for its help with this story.

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