Commercial · LA · Orange · Ventura · San Bernardino · Riverside Counties
Commercial Kitchen Exhaust Hood Repair
Fan motor not running, weak airflow, smoke staying in the kitchen, Type I (grease) and Type II (heat/condensate) hood repair, exhaust fan service, and make-up air (MUA) units. Captive-Aire, Gaylord, Halton, Greenheck, Accurex, Loren Cook. NFPA 96 compliant service across LA, Orange, Ventura, San Bernardino & Riverside counties. Same day.
Our Branches
8 service territories across Southern California
Commercial Kitchen Exhaust Hood Repair
Southern California
01, About This Service
A commercial kitchen exhaust hood that isn't pulling air is a fire code violation, not just an inconvenience.
In California, cooking equipment that produces grease-laden vapors, fryers, charbroilers, woks, open-flame ranges, must operate under a functioning Type I exhaust hood. This isn't a recommendation. It's required under NFPA 96, the California Fire Code, and locally enforced by the fire authority for your county (LAFD in LA, OCFA in Orange County, Ventura County Fire, San Bernardino County Fire, Riverside County Fire). A hood that's not ventilating allows grease vapor to accumulate in the kitchen and ductwork, the primary precursor to kitchen grease fires, which account for a significant portion of commercial kitchen fires across SoCal every year.
We repair commercial kitchen exhaust hood systems across all five SoCal counties: exhaust fan motor and blower replacement, belt and bearing service, speed control and switch repair, baffle and grease filter service, make-up air (MUA) unit repair, and ductwork access. We service Captive-Aire, Gaylord, Halton, Accurex, and Streivor hood systems along with Greenheck, Loren Cook, and Twin City Fan exhaust fans, plus custom-fabricated stainless hoods common in older restaurant buildings from DTLA's Historic Core to OC's coastal restaurant rows. The mechanical repair of the hood and ventilation system, the components that move air, is our scope. NFPA 96 grease duct cleaning is a separate specialized service performed by certified hood cleaning contractors; we can refer you to certified cleaners for that component.
A commercial kitchen filling with smoke during service is a fire safety emergency, not a comfort issue. If your exhaust system is not removing smoke and grease vapor from over active cooking equipment, stop service and call (424) 325-0520. Operating cooking equipment under a non-functioning Type I hood creates grease accumulation conditions associated with kitchen fires. We dispatch these calls immediately.
02, Type I vs. Type II Hood, Critical Distinction
Two completely different systems with different compliance requirements. Know which one you have.
Most restaurant operators know they have a "hood", fewer know which type, and it matters significantly for both repair approach and compliance obligations.
Over cooking equipment producing grease-laden vapors
Required over fryers, charbroilers, open-flame ranges, woks, griddles, any equipment that produces airborne grease particles. Must include grease filters or baffle filters, a grease collection trough, and in California, a UL-300 listed fire suppression system.
NFPA 96 governs Type I hoods, requires semi-annual grease duct cleaning by certified contractors, documented and reported to the fire marshal. Non-compliance is a fire code violation.
- Grease/baffle filters required
- Grease drain and collection pan
- Fire suppression system (ANSUL)
- Listed and labeled construction
- NFPA 96 semi-annual cleaning
- LAFD inspection compliance
Over equipment producing heat, steam, or odors without significant grease
Required over dishwashers, steamers, ovens (no open flame), coffee equipment, and other heat-producing appliances that do not generate grease-laden vapors. Less stringent construction requirements, no fire suppression required.
No NFPA 96 requirement, but still regulated under mechanical code for adequate ventilation. Failure still affects kitchen comfort, health code compliance for condensation management, and equipment longevity.
- No grease filters required
- No fire suppression required
- Less stringent construction
- Still requires adequate CFM
- Mechanical code compliance
- Regular fan service recommended
03, Compliance Requirements (NFPA 96 + California Fire Code)
NFPA 96, California Fire Code, county fire and health authorities, what SoCal restaurant operators need to know
A non-functioning exhaust hood can trigger citations, closure orders, and insurance denial
Across Southern California, commercial kitchen ventilation requirements are enforced through overlapping authority: NFPA 96 (National Fire Protection Association Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations) adopted by the California Fire Code, local fire departments that conduct inspections and issue citations (LAFD in LA County, OCFA in Orange, Ventura County Fire, San Bernardino County Fire, Riverside County Fire), and county building-and-safety departments that regulate mechanical systems. A kitchen fire that occurs under a non-compliant or malfunctioning hood can result in insurance claim denial, carriers increasingly require proof of NFPA 96 compliance.
NFPA 96 Standard Table 11.4, Inspection & Cleaning Cadence
Required cleaning frequency by cooking volume. Note: this is the cleaning obligation (performed by certified hood cleaning contractors). Mechanical repair, what we do, is a separate scope but typically gets scheduled on the same visit.
Documentation must be retained on-site and produced for fire inspector on request. Failure to maintain or produce documentation is treated as the same violation as not cleaning.
04, Make-Up Air (MUA) Repair
Hood + MUA is a paired system. If one is down, the kitchen is in negative pressure.
The single biggest topical hole on most exhaust-hood pages, and the one we get the most "weird" calls about. Every CFM the exhaust pulls out has to be replaced by tempered make-up air, or the kitchen ventilation collapses regardless of how strong the exhaust fan is.
What MUA failure looks like in the field
MUA failure rarely presents as "MUA isn't working." It presents as one of these symptoms, all of which point at the supply side, not the exhaust side:
- Exhaust seems weak even though the fan is running fine. The hood physically cannot move air the kitchen can't replace.
- Back-doors blow open or won't open against pressure. Negative pressure pulls outside air through every opening.
- Gas appliances develop yellow-tip flames or back-draft. Combustion air is being starved.
- Kitchen smells like outside air dust, exhaust from neighbor restaurant, or the alley dumpster. Air is being pulled inward through unintended pathways.
- Pilot lights blow out unexpectedly. Same root cause as the back-draft symptom.
- Walk-in cooler doors slam open or won't seal. Pressure differential propagates through the kitchen.
What we service on the MUA side
MUA Fan Motor & Belt
Same failure modes as the exhaust fan, bearings, motor windings, belts on belt-drive systems. Greenheck KSF / RGS, Captive-Aire A1-D series, Loren Cook MA series.
Heated MUA, Gas Burner
Gas-fired make-up air units have a burner section to temper incoming air on cold mornings. Burner ignition modules, gas valves, flame sensors, and thermostatic controls. Critical for SoCal winter mornings when outside air is below 50°F.
Cooled MUA, Evaporative
Evaporative cooler MUA units (common in inland SoCal, San Bernardino, Riverside, San Fernando Valley). Pad replacement, water-distribution lines, sump pump, float valve, blower service.
Damper Actuators & Controls
Modulating dampers that match MUA airflow to exhaust airflow on demand. Failed actuator = fixed-position MUA = either over- or under-supplying. Belimo, Honeywell, Johnson Controls actuators.
Filters & Pre-Filters
MUA filters degrade faster than HVAC filters because they're handling 100% outside air with full dust load. Replacement on schedule prevents fan motor strain and keeps grease-laden ambient (from neighbor restaurants in dense areas like Koreatown or Anaheim's restaurant row) from being pulled into the kitchen.
Hood + MUA Balancing
After any major repair on either side, the system has to be re-balanced, exhaust CFM and supply CFM matched within ~10%. We measure with anemometer at multiple points and tune fan speed to spec.
05, Exhaust Fan Repair
Upblast roof fans, inline duct fans, centrifugal blowers, every commercial fan configuration
The exhaust fan is its own service category alongside the hood itself, different access (rooftop vs duct vs blower box), different brands, and different decision points (bearing vs motor, belt vs direct-drive).
Upblast Roof Fans
Greenheck CUE / CUBE, Loren Cook ACE / ACRU, Captive-Aire DR series. Roof-mounted, belt-driven or direct-drive, and the most common configuration on SoCal restaurant buildings. Bearing failures are the dominant issue here, UV and rooftop heat accelerate bearing seal degradation. We service the bearings on-roof when possible; full motor swap when not.
Inline Duct Fans
Greenheck SQ / BSQ, Twin City TCB inline. Mounted in the duct run between the hood and the roof, used when rooftop access is restricted (multi-story buildings, historic structures). Access requires duct opening; we plan the work around service hours.
Centrifugal Blower Assemblies
Hood-integrated centrifugal blowers (common on Captive-Aire and Gaylord factory-paired hood-and-blower units). Squirrel-cage wheel, motor, and housing as one assembly. When a blower wheel is damaged from a bearing seizure, the full assembly is typically replaced rather than rebuilt.
Belt-Drive vs Direct-Drive
Belt-drive systems are more serviceable (belt + pulleys are wear items, replaced regularly) but require periodic alignment. Direct-drive is simpler but a motor failure means a full motor swap rather than a belt replacement. We recommend belt-drive for high-CFM systems and direct-drive for sub-2HP applications.
Bearing Replace vs Motor Swap
Catch bearing wear early (grinding noise, increased vibration) and a bearing swap is $200–$450. Wait until the bearing seizes and damages the rotor or blower wheel, and you're at $600–$1,400+. We diagnose runout with a dial indicator on every fan service call so we catch the early warning.
VFD & Speed Control
Variable frequency drives (VFD) on energy-management hood systems (Halton M.A.R.V.E.L., Captive-Aire CORE) ramp fan speed up and down based on cooking activity. IGBT module failures lock the system at maximum or fail to start, we replace VFD modules with manufacturer-compatible parts.
06, Common Failures We Repair
What our technicians diagnose most often in SoCal commercial hood systems
Fan Motor Not Running / No Airflow
Failed exhaust fan motor, the most common mechanical failure in commercial hood systems. Hood appears operational (lights on, controls working) but no air movement. Motor failure from bearing seizure, winding burnout, or capacitor failure. On belt-drive systems, a broken belt produces the same symptom with the motor running but the fan not spinning. We carry motors and belts for common Captive-Aire and Gaylord configurations.
Weak Airflow / Reduced Capture
Four causes in order of likelihood: (1) grease-loaded baffle filters blocking airflow, check and clean/replace first; (2) grease accumulation in the ductwork reducing duct cross-section, requires certified hood cleaning service; (3) worn fan belt reducing blower speed on belt-drive systems; (4) failing motor running below rated RPM from bearing wear. Weak airflow is the early warning before complete failure.
Excessive Noise / Vibration
Worn or failed fan bearings, the most common noise source in commercial hood blower assemblies. A deep grinding or rumbling sound that worsens over time. Bearing failure on upblast fans (roof-mounted) is particularly common in SoCal's UV and rooftop-heat environment which accelerates bearing seal degradation, Inland Empire summer roof temps regularly hit 140°F+. Catch it early: a bearing replacement is $200–$400; a seized bearing that damages the blower wheel is $600–$1,200.
Hood Running Constantly / Won't Turn Off
Failed speed control or control switch, the interlock between the cooking equipment and the hood. Many commercial hood systems are interlocked to the cooking equipment: the hood turns on automatically when cooking equipment is activated. A failed relay or control board can lock the hood in continuous run mode, or conversely prevent it from activating when needed. Control board and switch replacement is typically a $200–$400 repair.
Grease Dripping / Leaking
Overfull grease collection cups or damaged grease channel, this is a cleaning maintenance issue that becomes a repair issue when the collection system is damaged. Grease dripping from a hood onto cooking surfaces or floors is a county health-code violation (LADPH, OC Health Care Agency, etc.) and a fire risk. We inspect and repair grease collection channels and drain components as part of hood service visits.
Residential / Semi-Commercial Range Hood
For residential and semi-commercial range hoods (Viking, Wolf, Broan, Vent-A-Hood, Zephyr), the repair is different from commercial hood service, simpler motor systems, different filter types, and no NFPA 96 compliance requirement. We service these as part of our residential appliance repair. See our Range Hood Repair page for residential hood service.
06.5 · Failure-mode service + brands
Sub-services and brand-specific coverage.
Failure-mode subs cover specific symptoms in depth; brand pages cover manufacturer-specific patterns.
- Exhaust fan not working — Motor burnout, belt drive wear, bearing failure, control wiring, NFPA 96 grease impact on fan blade balance.
- Grease buildup + NFPA 96 cleaning — Cleaning cadence by cooking volume, baffle filter replacement, duct degreasing, LADWP hard water on water-wash systems.
- Fire suppression coordination — Hood-side coordination with Ansul R-102, Pyro-Chem KitchenGard. Gas shut-off valve, fusible link, manual pull, NFPA 96 + UL-300 cycle alignment.
- Hood cleaning service · Make-up air system · Type 1 hood
- Greenheck (Schofield WI independent, premium tier) · Vent Master (UV-light grease management specialty) · CaptiveAire
07, Pricing
Commercial exhaust hood repair cost, complete breakdown
The most searched question about exhaust hood service is cost. Here's every component, honestly priced.
| Service / Repair | Cost Range | Notes |
|---|---|---|
| Commercial Diagnostic | $120 | Applied to repair if approved |
| Exhaust Fan Motor (small, <1 HP) | $280–$420 | Inline fans, small upblast units |
| Exhaust Fan Motor (large, 1–3 HP) | $420–$650 | High-volume restaurant upblast fans |
| Fan Bearing Replacement | $200–$450 | Price rises significantly if bearing seizes and damages blower wheel |
| Drive Belt Replacement | $150–$250 | Includes belt tension and pulley alignment check |
| Speed Control / Switch Repair | $180–$380 | Control board, relay, or switch assembly |
| Baffle Filter Cleaning | $80–$160 | Per filter bank. Full NFPA 96 duct cleaning requires certified hood cleaning contractor, separate service |
| Grease Collection System Repair | $120–$300 | Collection cup, drain channel, or grease trap repair |
| Full Blower Assembly Replacement | $600–$1,400+ | When motor + blower wheel both require replacement; varies by unit size |
Important: NFPA 96 grease duct cleaning, the full duct and plenum cleaning required by fire code, is performed by certified hood cleaning contractors, not general appliance repair companies. This is a separate service from the mechanical repairs we perform. Most certified hood cleaning companies across SoCal charge $300–$800 for a full cleaning depending on hood size and duct length. We can refer you to certified cleaners in your county if needed. Our 90-day warranty covers all mechanical parts and labor.
08, Brands We Service
Commercial exhaust hood and fan brands across SoCal restaurant kitchens
Dedicated brand pages
Also installed across SoCal, we service these too
Gaylord, long-established independent
Gaylord Industries (Tualatin OR) has manufactured commercial hoods independently since 1959. Real SoCal install base at older restaurant, bakery, and institutional kitchens, our techs service Gaylord G-series Type I/II canopies, ELXC ventilators, UVi UV-treated grease systems, and RSPC recirculating systems.
Streivor, California local manufacturer
Streivor Air Systems (Stockton CA) has manufactured commercial kitchen ventilation since 1981. California-corridor parts chain (1–3 day SoCal delivery vs East Coast OEM 5–10 day) is the operational angle. We service Streivor SLM low-profile canopies, island canopies, and back-shelf hoods across SoCal restaurant and institutional kitchens.
Greenheck, commercial fan specialist
Greenheck (Schofield WI) has been the US market leader in commercial fans and ventilation since 1947. Our scope on Greenheck: CUE and CUBE upblast roof exhaust fans, KFD kitchen-hood-coupled fans, and ductwork-integration diagnostic. Fan + ductwork + roof penetration scope differs from pure hood-assembly work, we stage the diagnostic across both.
Loren Cook, upblast fan specialist
Loren Cook Company (Springfield MO, since 1941) is the upblast and centrifugal fan specialist most commonly seen on SoCal restaurant rooftops alongside Greenheck. Our scope on Loren Cook: ACE and ACRU upblast roof exhausters, MA make-up air units, ducted inline fans. Bearing service and motor swaps are routine on Loren Cook installations.
Twin City Fan, industrial-grade ventilation
Twin City Fan & Blower (Plymouth MN, since 1972) builds industrial-grade fans common in newer SoCal commercial construction, TCB inline duct fans, TCBR centrifugal blowers, and large-CFM upblast units used on hospital and institutional kitchens. We service motor, bearing, belt, and damper components.
For residential and semi-commercial range hoods (Viking, Wolf range hoods, residential Broan, Vent-A-Hood, Zephyr), see our residential range hood repair page, separate $89-diagnostic scope with a different installed base.
09, Recent Repairs
What our technicians actually fixed recently
"Kitchen filling with smoke during dinner service, hood not pulling"
Failed exhaust fan motor on a Captive-Aire upblast fan unit mounted on the roof above a Hollywood restaurant's kitchen. The motor had failed from bearing seizure, it had been making a progressively louder grinding sound for approximately three weeks before failing completely during a busy Friday dinner service. The kitchen was filling with smoke and grease vapor within minutes of service beginning, forcing the restaurant to reduce cooking activity significantly.
"Hood not running since this morning, health inspection next week"
Failed control relay on a custom-fabricated stainless Type I hood over a Koreatown Korean BBQ restaurant's tabletop grills. The control relay, the component that receives the signal from the cooking equipment interlock and activates the hood blower, had failed open, preventing the blower from starting. The restaurant had a LADPH health inspection scheduled for the following week and was correctly concerned that a non-functioning hood over charcoal and gas grills would be cited.
"Hood stuck on high speed, won't reduce for quieter sections of service"
Failed variable speed drive (VFD) on a Halton energy-management hood system in a Newport Beach coastal gastropub. The M.A.R.V.E.L. system uses sensors to detect cooking activity and adjust exhaust fan speed accordingly, running at lower speed (and noise) during slow periods and ramping up automatically during high-heat cooking. The VFD had developed a fault that locked the system at maximum speed, making the dining room unacceptably loud during quieter service periods. Coastal salt-air corrosion at the VFD heatsink fins was a contributing factor, a recurring failure pattern on Newport-Huntington-Laguna restaurant rooftops.
"Grinding noise from roof fan, getting louder every week"
Failing fan bearings on a Loren Cook ACE upblast roof exhauster over a Thousand Oaks Thai restaurant operating an Accurex hood. The grinding sound had been noted for approximately five weeks and had been getting progressively worse, consistent with bearing cage wear progressing toward bearing failure. Thai cooking, with its high-heat wok technique and frequent use of aromatic spices and oils, produces a demanding exhaust load that accelerates bearing wear in rooftop fan environments exposed to Conejo Valley UV and summer heat (rooftop temps regularly hit 130°F+ on a July afternoon).
10, Frequently Asked Questions
Commercial exhaust hood repair, what SoCal operators ask us
How much does commercial exhaust hood repair cost?
Diagnostic is $120, applied to repair if approved. Fan motor replacement runs $280–$650 depending on motor size. Bearing replacement $200–$450. Belt replacement $150–$250. Speed control $180–$380. Full blower assembly $600–$1,400+. MUA unit work runs $250–$800+ depending on the failed component. See the detailed cost table above for the complete breakdown. NFPA 96 grease duct cleaning is a separate service from mechanical repair, $300–$800 from certified hood cleaning contractors.
Which areas of Southern California do you cover?
All five SoCal counties: Los Angeles, Orange, Ventura, San Bernardino, and Riverside. We dispatch from 8 service territories so the technician on your hood call is coming from the closest one. Hood failures over active cooking equipment are emergency priority dispatch in every county.
Do you also repair make-up air units (MUA)?
Yes. Hood + MUA is a paired system, every CFM the exhaust pulls out has to be replaced by tempered make-up air, or the kitchen goes into negative pressure (back-drafts, doors that won't open, gas appliances starving for combustion air). MUA failure typically presents as "exhaust seems weak even though the fan is fine." We service MUA fans, gas burners (heated MUA), evaporative coolers (cooled MUA), filters, and damper actuators.
What's the difference between a Type I and Type II commercial hood?
Type I hoods are over grease-producing cooking equipment (fryers, ranges, charbroilers, woks) and require grease filters, fire suppression, and NFPA 96 periodic cleaning. Type II hoods are over non-grease equipment (steamers, dishwashers, ovens) and have less stringent requirements. The repair approach differs, Type I has grease collection systems that Type II does not. Tell us which type you have when you call.
My restaurant hood is not pulling air, what should I check first?
Check the baffle or grease filters first. Heavily grease-loaded filters significantly reduce airflow and are the most common cause of weak ventilation. Remove them and check, if heavily coated, cleaning or replacing them may restore airflow without mechanical repair. Second, verify the make-up air unit (MUA) is running, if MUA is down, exhaust collapses regardless of fan condition. Third, if filters are clean and MUA is running, call us at (424) 325-0520.
Is a broken exhaust hood a fire code violation?
Yes, for Type I applications over grease-producing cooking equipment. A non-functioning Type I hood is a violation under NFPA 96 and the California Fire Code, enforced by the local fire authority for your county (LAFD, OCFA, Ventura County Fire, San Bernardino County Fire, Riverside County Fire). Cooking without functioning exhaust ventilation over open flame or fryer equipment allows grease vapor accumulation, a direct fire risk and a citable violation during fire inspection.
Do you do the NFPA 96 hood cleaning as well?
No, NFPA 96 grease duct cleaning requires specialized equipment and certified contractors separate from appliance repair. We do the mechanical repairs (motor, bearing, belt, controls, MUA). If you need a certified hood cleaning company, we can refer you to one in your county. Many operators schedule both services on the same day for efficiency.
Do you repair Captive-Aire, Gaylord, Halton, and Greenheck commercial hoods and fans?
Yes. Captive-Aire, Gaylord, Halton, and Accurex are the major commercial hood brands we service across SoCal. On the fan side: Greenheck (CUE/CUBE upblast), Loren Cook (ACE/ACRU), Twin City Fan, and Captive-Aire integrated fans. Custom stainless fabricated hoods are also common in older restaurant buildings, we service the fan and control components on these as well.
11, Related Commercial Services
Complete commercial kitchen repair across Southern California
Counties We Serve
5 counties · 8 service territories. Same-day commercial dispatch from the closest branch. Hood failures over active cooking equipment are emergency priority.
Commercial kitchen exhaust hood repair across Southern California, same-day priority
Captive-Aire, Gaylord, Halton, Greenheck, Accurex, Loren Cook, Twin City Fan. Type I & Type II hoods, exhaust fans, MUA units. 5 counties · BHGS #A49573 · NFPA 96 compliant. $120 diagnostic, 90-day warranty.