The 86 Repairs Guide to Restaurant Hood Systems

When in doubt, vent your kitchen out. Get our preventative maintenance, troubleshooting, and warranty tips for restaurant hood systems in this guide.


Welcome to another 86 Repairs Guide! In this series, we provide valuable troubleshooting, preventative maintenance, and warranty information on the equipment and infrastructure found in your restaurant. We hope this information will help you and your team become more informed about repairs and maintenance (R&M)—and save you time and money along the way.

Working in restaurants, you already know that a lot of venting happens in the kitchen:

“That eight top only left me a $10 tip!”

“Table 28 sent their steak back…again.”

“This lady in the drive-thru is demanding a catering order for 40 right now!”

Folks in the trenches need to let off steam to keep their cool. But did you know the equipment in your kitchen needs to let some steam off, too? Enter an unsung hero of the back of house: restaurant hoods.

Hood systems collect the hot, polluted air produced while cooking and replace it with temperate, clean air, keeping everyone inside comfortable and safe from contaminants.

If the hood isn’t working properly or won’t turn on at all, kitchens quickly become hot, smoky, and out of compliance with local health codes.

Don’t let equipment failures abduct your restaurant. Check out our preventative maintenance, troubleshooting, and warranty advice for hood systems in this guide.

Table of Contents

What is a restaurant hood system?

A restaurant hood system is a type of ventilation that pulls things like fumes, smoke, steam, and exhaust out of the kitchen and replaces them with fresh air. You may also know it as an exhaust hood or range hood. Hood systems are required in every kitchen that contains hot side units, and they’re also extremely common in kitchens with large commercial dishwashers.

Restaurant hood systems are essentially their own HVAC systems. They include the hood itself, which collects pollutants; an exhaust fan, which mechanically pulls the pollutants up and out of the kitchen; and a makeup system, which is a vent directly in front of the hood that replaces polluted air with fresh air. The makeup system cools or heats air to keep cooks comfortable, creates an air curtain so fumes stay under the hood, and balances air pressure. 

But why do those pollutants need to be pulled out in the first place? For one, it prevents the buildup of smoke and fumes. It also helps keep the chefs and cooks on the line cool, exchanging hot air from the oven or kitchen with something temperate from outside.

Most importantly, restaurant hood systems help collect the oil that collects in a kitchen. If a hood isn’t working properly, or if its grease trays are too full, those oils can ignite and create a massive column of flames that’s extremely difficult to put out. This leaves the entire building at risk of burning down, jeopardizing the well-being of your staff, customers, and community.

Leave the inferno to Dante. Preventative maintenance can help your hood system run as it should, and troubleshooting might avoid expensive vendor invoices and downtime.

Numbers to know about restaurant HVAC

Because restaurant hood systems act as their own HVAC units, we log their repair data with other HVAC infrastructure issues reported by our customers.

In our annual report, The State of Repairs, we shared that HVAC issues comprised 12.4% of repair requests from restaurants in 2021. That’s pretty significant when you consider every other piece of equipment in a kitchen—and pretty concerning when you learn the average cost of HVAC repairs.

  • The average invoice cost to repair an HVAC issue in 2021 was $1,019.90—the most expensive out of all other equipment types included in the report.
  • The first-time fix rate for HVAC issues was pretty poor, coming in at 88.3%. This means that, 11.7% of the time, restaurants needed to pay at least a second vendor invoice to resolve the issue! 

With expenses high and success rates low, restaurants must be proactive about hood system maintenance and troubleshooting before emergency strikes.

Preventative maintenance for restaurant hood systems

Preventive maintenance for restaurants helps businesses avoid downtime and unnecessary breakdowns, all while reducing maintenance costs and extensive lead times on parts and labor. Here are some simple preventative maintenance ideas you can implement for the hood systems in your restaurants:

Routine cleaning

We’ve said it before, and we’ll say it again: hood systems act as their own HVAC systems. Because of how complicated they are, the vast majority of cleaning is done by contracted vendors.

Hood systems that aren’t cleaned pose a fire hazard to your restaurant. So be sure to check with your manufacturer and local health code regulations to set cleaning appointments for your hood as part of your overall preventative maintenance schedules.

Empty grease trays

As oils and fumes condense inside the hood, the grease will drop down into the grease trays on the unit. These should never be anywhere close to full—otherwise, you risk creating a deadly column of fire. (Sounds dramatic, but it’s true.)

Check and empty the grease trays bi-weekly or monthly to make sure you’re safe.

Clean baffles

Restaurant hoods contain filters known as baffles that can be removed and cleaned for optimal pollutant removal.

To find the baffles on your unit, look at the back of the hood for pleated panels with small metal handles. Lift and remove them and clean them with a degreasing solution. Before putting them back, make sure they’re completely dry.

Replace exhaust fan belt

Is there an annoying squeak or rumble coming from under the restaurant hood? The belt attached to the exhaust fan probably needs to be replaced. 

On your restaurant roof, look for a mushroom-shaped unit—this is your exhaust fan. Turn off the unit with the attached power switch and flip open the fan. There should be a rubber belt attaching a motor to the fan blades. If it’s falling apart or broken entirely, change it out.

Look for writing on the outside of the belt. These are the specs you need when you buy a replacement belt, including length, number of teeth, and the distance between each tooth. Use those specs to pick out the proper replacement in-store or online.

Restaurant hood system troubleshooting tips

If your hood system isn’t working properly, there are a few things you can look into to try and resolve the issue before you spend the time and money on an HVAC vendor:

Hood won't turn on

If your vent hood won’t turn on, you can’t remove the polluted air from your kitchen and create an unsafe, and highly scented, environment for your employees and guests. Before you call a vendor, 

  • Check the breaker panel for your hood breakers. Toggle them off for 30 seconds and back on, and verify the fans are blowing. 
  • Check the exhaust fan to ensure the motor and belt are functioning properly.
    • If the fan won’t turn on, your belt might have broken.
  • If you have a hood system with a digital display, look at the panel to see if there’s an error code or suggestions for how to get the unit to run.
    • Use the manufacturer guide to check the codes and act accordingly.
      • To clear the control panel, you might need to reset the relays inside the panel. Proceed with caution: Do not do this unless you, or someone else on your team, are extremely comfortable with simple electric wiring techniques.
  • When in doubt, call your hood system manufacturer. CaptiveAire in particular has an extremely helpful service and technical support department.

If your hood still won’t turn on after running through those troubleshooting tips, it’s time to call in an expert.

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Replace exhaust fan belt

You want as many contaminants as possible captured in the grease traps of your hood system. If you notice grease streaks running down the unit, it’s because something in the unit isn’t working properly, causing oil and water to mix and drip out.

If this is happening,

  • Your exhaust fan might not be fully operational. Make sure the belt is still intact, and double-check to make sure the fan was not left open on the roof.
  • The hood might be due for a cleaning. Contact your preferred vendor to schedule service.

Makeup air unit misbehaving

Most issues with your makeup air unit for the restaurant hood system will need to be addressed. But before you call a vendor, keep in mind:

  • Toggling the breakers off and on will help you determine if electricity is the issue when air won’t come out of the unit.
  • During the first cold snap of the year, your hood system can only warm the air by about 40-50° F. Subzero days mean the air getting pulled into your kitchen will still be extremely cold—so even if the chef is complaining, the unit may still be working as it should.

Restaurant hood system warranties

Most restaurant hood systems don’t have long warranties. You’re likely looking at coverage for a year—two at best—and it won’t include commonly replaced parts like belts or lightbulbs.

Reach out to your manufacturer if you’re unsure about your warranty. And keep in mind that, if your restaurant is a new building that went up within the past year, you’ll need to check with your general contractor for warranty status. They’ll usually cover your repairs for that first year.

A final note on restaurant hood systems

Preventative maintenance on hood systems can protect your people from unsafe conditions, and troubleshooting can help avoid spending extra money on vendor dispatch. So the next time your hood is acting up, we hope you’ll use this guide to bring some fresh air into your approach to repairs.

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