Vent-A-Hood Magic Lung blower system: field service manual

Covers: Vent-A-Hood hoods and liners with Magic Lung centrifugal blowers (B100 single, B200 dual, T200/T400 island and multi-blower setups), plus notes on Power Lung low-profile and M-Line baffle models.

Single sourceBrands: Vent-A-Hood6 components

Vent-A-Hood is a premium Texas brand that uses no mesh filters on its Magic Lung units: the spinning blower wheel throws grease out of the air and into a removable housing and shield. Most service calls are about cleaning, wheel and motor matching, damper obstructions and installation (duct size, mounting height), not about failed parts.

Safety first

Turn the blower off before removing shields or housings; breaker off for any electrical or motor work.
Let lamps cool before changing.
Live voltage tests are caution work.
Do not bend the wheel or move balance clips.

How it works

Each Magic Lung blower is a motor with a blower wheel inside a removable housing. Air is spun so grease separates out by centrifugal force and collects in the housing and the removable E-Z Clean shield; Vent-A-Hood rates each blower at 300 CFM and says that equals about 450 CFM of a filtered hood.

Hoods combine blowers: B100 single (300 CFM), B200 dual (600 CFM), and larger wall or island setups up to eight blowers (2,400 CFM). In dual units, white wheels go on white motor rings and spin clockwise; black wheels go on black rings and spin counterclockwise. Mixing them kills performance.

Each blower has a damper above the housing that rests on the housing when the fan is off. Screws pushed into the duct are a common cause of a damper that cannot open.

Some models add SensaSource heat sensing that speeds the blower up when it senses high cooking heat. Hoods built since 2016 use LED lighting.

Components & tests

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work. © 2026 OnCall Tech. Original content; not a reproduction of any manufacturer document.Generic part photos (not of this brand): Chimney-style range hood with a glass canopy over a cooktop by Bilguun Gantumur, Pexels License

Diagnostic guides for this appliance

Guide · Range Hood

Range hood fan runs only on high, runs slow, or a speed is missing

On simple switch hoods, a missing speed is usually the switch or a failed winding tap; on board-controlled hoods it can be a relay on the control. A fan that is slow on every speed points to grease-dragged bearings, a weak run capacitor on PSC motors, or airflow restriction. Check mechanical drag and airflow before electrical parts.

8 steps ~45 minmoderate

Guide · Range Hood

Cold air, odors or insects coming in through the range hood when it's off

Two dampers should block the duct when the fan is off: one at the hood and one in the wall or roof cap. Grease, bends, missing springs or screws in the path keep them open. Long duct runs and a house under negative pressure make it worse. Fix the dampers first; make-up air questions go to code and an HVAC or licensed contractor.

7 steps ~60 minmoderate

Install · Range Hood

Range hood ducting: duct size, route, termination and makeup air

Hood performance depends more on the duct than the blower. Use the duct size the hood requires (never smaller), smooth metal duct, as few elbows as possible, and a proper wall or roof cap with a damper. Larger hoods can trigger a makeup-air requirement under local code (commonly when the hood can exhaust more than 400 CFM in homes with certain fuel-burning appliances).

6 steps ~240 minadvanced

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