1) Inspect Your Equipment
Before installing your roof mounted exhaust fan, inspect the equipment for any interior or exterior damage. Make sure you have all of the accessory items and that they are also damage free. Check for and retighten any bolts or screws that may have become loosened. Then, turn the blower wheel by hand to make sure that it is able to rotate freely.
2) Select and Prepare Your Site
The next step in installing your restaurant kitchen exhaust fan is to select and prepare the site where you will install it. Locate the fan as close as possible to the area it will be serving in order to limit any long or twisted duct runs. The fan discharge should be located at least 10 feet away from any supply intakes.
Confirm that your fan supports are strong enough to hold your equipment and make sure you have enough clearance around your installation site to safely set up your equipment and lift it into its final position. And of course, before installing or servicing any commercial kitchen exhaust equipment, always disconnect the power.
3) Curb and Ductwork
Most rooftop ventilators are designed to be installed on top of a prefabricated or factory built roof curb. Follow the curb manufacturer’s instructions for proper curb installation. Roof curbs should be connected to structural roof members with at least four lug screws, anchor bolts, or other appropriate fasteners per curb flange.
Curb flanges should be caulked to the roof. The fan should be installed on a curb and/or rail elevated no less than 14” above any surface. Be sure that the duct connection and fan outlet are properly aligned and sealed. Then, secure the fan to the curb through the vertical portion of the ventilator base assembly flange using a minimum of eight lug screws, anchor bolts, or other appropriate fasteners.
Depending on the type of curb installation and roofing material, shims may also be required. When you are done installing, double check all fasteners for tightness.
4) Roof Mounting
The roof mounted upblast exhaust fans sold by HoodFilters.com are specified for a specific CFM and static pressure. The ductwork attached to these units can significantly affect their airflow performance. Due to this, it is important that flexible ductwork and square elbows not be used. It is also very important to avoid unnecessary transitions and turns in the ductwork near the fan inlet. These can cause system effect and drastically increase the static pressure while reducing the airflow.
For more information, you can refer to the guides and recommendations for duct runs set forth by the Sheet Metal & Air Conditioning Contractors’ National Association.
If your ventilation system requires a backdraft damper, you would install that first and secure it within the roof curb. A note of caution— National Fire Protection Association (NFPA) 96 fire codes recommend that dampers should not be installed when an exhauster is used for the removal of smoke and/or grease laden vapors from commercial kitchen equipment. You should also consult with your state and local codes for any more detailed requirements.
In accordance with NFPA 96, if you are installing an upblast kitchen hood exhaust fan, you will need to ensure that the discharge is at least 40 inches above the rooftop. Run the power cord through the conduit tube, which is located on the top skirt, outside of the unit. Then, secure the ventilator curb through the vertical portion of the ventilator base assembly flange using lug screws, anchor bolts, or other suitable fasteners.
Now it’s time to connect the fan motor to your power source. Check to make sure that the voltage and phase of the power supply and the wire amperage capacity are compatible with the requirements listed on the nameplate of your fan motor.
Make sure the power line wiring is de-energized. Also, be sure to lock and tag the disconnect switch or breaker to prevent an accidental power up. The disconnect switch is located on the exterior of upblast fans and in the interior of downblast fans. On downblast direct drive fans, the disconnect function is built into the speed controller.
According to the National Electric Code, short circuit protection should be supplied by a dedicated branch circuit that is run to a junction box. Before you power up the fan, check the ventilator wheel again for free rotation and make sure that the interior of the fan is free of any loose debris or shipping materials. Be sure to check all fasteners for tightness and then re-install the motor dome. Please note that if any of the original wire supplied with the fan has be replaced, it must be replaced with type TW wire or equivalent.
6) Roof Mounted Exhaust Fan Accessories
A grease pipe is usually positioned towards the roof slope to provide single-point drainage of water and residue. Some means for collection such as an exhaust fan grease box must be provided. It can be placed directly under the exhaust fan trough or an adapter and pipe can be used to carry the water and residue to a remote collection point. HoodFilters.com offers a wide range of rooftop grease containment systems to suit any need.
Code 188.8.131.52 of the NFPA 96 fire codes states that “approved upblast fans with motors surrounded by the airstream shall be hinged.” Not only is it required, but a hinged exhaust fan is also much safer and easier to clean and maintain. So when installing a roof mounted fan, it’s smart idea to also go ahead and install an exhaust fan hinge kit. HoodFilters.com carries twenty different hinge kits to meet the needs of a variety of budgets and fan sizes. Please note that exhaust fans with hinge kits require extra slack in the wiring to the fan to allow it to be tilted back to a fully open position.
Another affordable solution to NFPA fire code requirements is our weatherproof exhaust fan access panel. It can be installed in less than 30 minutes and provides a four-inch opening for easy inspection and cleaning of fan blades.
One of our most popular roof mounted fan accessories is our exhaust fan safety handle. These unique handles provide a safer way to lift and close the inner fan and duct work without causing any damage to the fan bowl or seals. By providing easier access, they help prevent maintenance issues during cleaning, servicing, and fire inspection.
Before attempting to assemble, install, operate or maintain any commercial kitchen ventilation equipment, it is important to carefully read and save all of the materials that came with the product. And of course, protect your equipment, yourself, and those around you by observing all safety information.
If you have any questions about installing your roof mount fan, feel free to give our customer service specialists a call at 877.394.9731 or live chat with us on our website.