How to Replace a Commercial Kitchen Exhaust Fan Motor

Introduction

Replacing a commercial kitchen exhaust fan motor is an important maintenance task that helps keep your kitchen ventilation system running properly. As the fan motor starts to wear out over time, it can reduce airflow, increase noise levels, and eventually fail completely. By learning how to replace the motor yourself, you can avoid costly repairs and keep your kitchen exhaust system operating at peak performance. In this guide, I will walk through the complete process of replacing a commercial kitchen exhaust fan motor step-by-step.

Reasons to Replace a Commercial Kitchen Exhaust Fan Motor

Here are some common signs that it may be time to replace the exhaust fan motor in your commercial kitchen:

• Reduced airflow - As the fan motor bearings wear out, the fan blades spin slower, reducing exhaust ventilation. This allows heat, smoke and odors to build up.

• Increased noise - Worn out motors and bearings cause the fan to run louder. This adds unwanted noise pollution to the kitchen environment.

• Motor overheating - When bearings fail, motors have to work harder to turn the fan. This can lead to overheating, shorting out and failure.

• Visible damage - If you notice cracked housings, bent blades or frayed wiring, this indicates the fan motor is failing. Replacement is needed.

• Age - Standard lifespan of a commercial kitchen exhaust fan motor is 10 years. Older units should be preemptively replaced.

Replacing the motor before total failure occurs helps prevent disruption to kitchen operations during peak hours.

Choosing a Replacement Exhaust Fan Motor

When selecting a new exhaust fan motor, you need to match:

• Horsepower - Check nameplate for required HP rating and match new motor.
• RPM - Revolutions per minute should match existing setup.
• Phase - Single or three phase power supply compatibility.
• Voltage - Usually 115V or 208V.
• Frame size - Needs to fit existing bracket mounts.
• Shaft size - Diameter and length must match the fan blade assembly.

Also consider getting a motor with sealed bearings and thermal overload protection for maximum longevity. Contact the exhaust hood manufacturer if unsure of exact replacement needs.

Tools and Materials Needed

Before starting this project, make sure you have the necessary tools and replacement parts:

• Replacement exhaust fan motor - Match specs of old motor.
• Electrical tape - For securing wire connections.
• Wire cutters - For removing old motor wires.
• Adjustable wrench - For loosening mounting bracket nuts.
• Screwdriver - For accessing wiring connections.
• Voltmeter - For testing electrical system.
• Ladder - For accessing roof or ceiling mounted fans.

You may also need conduit fittings, wire nuts and crimp connectors depending on wiring setup.

Safety Precautions

When working with electrical motors and commercial kitchen ventilation systems, safety should always be the top concern:

• Turn off power supply at breaker before starting.
• Verify power is off with a voltmeter before proceeding.
• Allow system to cool before handling - burns are likely!
• Do not change wiring while system is energized.
• Have a fire extinguisher on hand.
• Follow lock out/tag out procedures.
• Use caution when working at height on a ladder.
• Wear protective gloves, eyewear and non-slip shoes.

Follow all local and national electrical codes for commercial kitchens to ensure safety.

Step-by-Step Motor Replacement

Once you are fully prepared, follow these steps to replace the exhaust fan motor:

Turn Off Power

• Locate the circuit breaker powering the exhaust fan and switch it to OFF.
• Double check wires with a voltmeter to verify power is off.

Remove Fan Blades

• Unbolt the fan blades from the motor shaft using an adjustable wrench.
• Carefully remove blades and set aside.

Disconnect Wiring

• Remove wiring compartment cover.
• Label and disconnect all wiring from old motor.
• Cut wires leaving enough length to reconnect.

Remove Motor Mounting

• Support motor weight before loosening brackets.
• Using wrench, loosen mounting nuts and bolts.
• Carefully remove old motor from exhaust hood.

Install New Motor

• Place new motor on mounting bracket.
• Reinstall bolts and nuts to fasten in place.

Connect New Wiring

• Match wire colors from old motor.
• Securely connect wires using wire nuts and electrical tape.
• Replace wiring compartment cover.

Reattach Fan Blades

• Slide fan blades onto new motor shaft.
• Tighten bolts securely using your wrench.

Restore Power and Test

• Turn circuit breaker back ON.
• Verify proper operation and check for vibrations.

Following proper safety precautions and these steps will allow you to get your commercial kitchen exhaust fan running like new again with a replaced motor. Be sure to inspect the fan blades and mounting bracket while doing this repair to replace any other worn parts as needed. Taking care of small issues before they become big problems will extend the life of your ventilation equipment.

When to Call a Professional

In some cases, it is best to have a licensed electrician or HVAC technician take care of the exhaust fan motor replacement:

• If you do not feel comfortable working with electrical wiring
• For fans requiring three phase power supplies
• If the fan blades also need balancing or replacement
• For repairs requiring ducting modifications or roof work
• If you lack the proper tools, equipment or workspace

Hiring a professional can often get the job done faster and ensure everything is up to code. But replacing a standard single phase exhaust fan motor is a DIY project an experienced handyman can usually tackle. Follow proper safety procedures and you can save on maintenance costs.

Conclusion

Regularly replacing worn commercial kitchen exhaust fan motors is essential for keeping your ventilation system running properly. Learning how to spot signs of a failing motor, choosing the right replacement model, taking proper safety precautions, and following the step-by-step installation process will allow you to complete this repair DIY. Or know when it makes sense to call in an electrical contractor. Proper ventilation keeps your kitchen operating safely and efficiently.