'%3e%3cpath%20d='M41.90,14.92%20L44.15,2.36%20L55.85,2.36%20L58.10,14.92%20A36%2036%200%200%201%2069.08,19.47%20L79.55,12.18%20L87.82,20.45%20L80.53,30.92%20A36%2036%200%200%201%2085.08,41.90%20L97.64,44.15%20L97.64,55.85%20L85.08,58.10%20A36%2036%200%200%201%2080.53,69.08%20L87.82,79.55%20L79.55,87.82%20L69.08,80.53%20A36%2036%200%200%201%2058.10,85.08%20L55.85,97.64%20L44.15,97.64%20L41.90,85.08%20A36%2036%200%200%201%2030.92,80.53%20L20.45,87.82%20L12.18,79.55%20L19.47,69.08%20A36%2036%200%200%201%2014.92,58.10%20L2.36,55.85%20L2.36,44.15%20L14.92,41.90%20A36%2036%200%200%201%2019.47,30.92%20L12.18,20.45%20L20.45,12.18%20L30.92,19.47%20A36%2036%200%200%201%2041.90,14.92%20Z'%20fill='url(%23cpGear)'%3e%3c/path%3e%3ccircle%20cx='50'%20cy='50'%20r='28'%20fill='none'%20stroke='%23012f00'%20stroke-width='3'%3e%3c/circle%3e%3cpath%20d='M43.50,37.50%20L45.50,35.50%20L54.50,35.50%20L56.50,37.50%20L56.50,43.50%20L62.50,43.50%20L64.50,45.50%20L64.50,54.50%20L62.50,56.50%20L56.50,56.50%20L56.50,62.50%20L54.50,64.50%20L45.50,64.50%20L43.50,62.50%20L43.50,56.50%20L37.50,56.50%20L35.50,54.50%20L35.50,45.50%20L37.50,43.50%20L43.50,43.50%20Z'%20fill='url(%23cpGold)'%20stroke='%23bf5d00'%20stroke-width='0.4'%20stroke-linejoin='miter'%3e%3c/path%3e%3c/g%3e%3c/svg%3e){kind=small}
Commercial Makeup Air Unit Service & Repair in NYC
When your makeup air unit fails, your kitchen exhaust hoods can't keep up, doors slam from negative pressure, and pilot lights blow out. Com+ Mechanical services and repairs direct-fired and indirect-fired MAUs for restaurants, commercial kitchens, and mixed-use buildings across the five boroughs and the greater NYC metro, restoring exhaust balance, heat, and code compliance fast.
Common Makeup Air Unit Problems We Fix
Kitchen goes negative — doors hard to open, hoods smoking over
The MAU isn't supplying enough makeup air to match exhaust, so the building goes negative. Hoods lose capture, smoke and grease spill into the kitchen and dining room, and exterior doors are hard to pull open. Usually a failed supply blower, a stuck or unpowered intake damper, a dirty filter bank, a tripped airflow proving switch, or a broken exhaust-fan interlock that never started the unit.
MAU runs but blows cold air into the kitchen
The blower is moving air but the burner isn't firing or modulating. On direct-fired units this is typically a failed ignition module, a faulty modulating gas valve or actuator, a tripped high-limit, or a bad discharge air temperature sensor. The unit dumps raw outdoor air, making the kitchen unworkable in cold weather and driving up the heat load on the rest of the building.
Burner won't light or locks out on safety
Direct-fired and indirect-fired burners lock out on ignition failure, flame loss, or a failed airflow/sail switch that won't prove. Causes include a dirty flame sensor or ignitor, low or unstable gas pressure, a clogged burner ribbon/profile, or a proving switch that never sees airflow because the blower or damper is faulty. The unit shuts down to prevent unsafe firing.
Rooftop unit short-cycles or trips its breaker
Frequent on/off cycling or nuisance breaker trips point to a failing blower motor or bearings, a VFD fault, a slipping or shredded belt, or a control sensor sending bad signals. Short-cycling hammers the gas valve and ignition, wastes fuel, and leaves the kitchen alternating between balanced and negative.
Hoods and MAU aren't interlocked or staged together
The makeup air unit should ramp up with the exhaust hoods through an interlock or demand-control kitchen ventilation signal. When that interlock fails or was never set up, the MAU runs out of sync — over-pressurizing when hoods are off or starving them when they're wide open. We restore proper staging so supply tracks exhaust.
Frozen or whistling unit / iced coil in winter
On indirect-fired or coil-equipped units, a failed temperature control or stuck damper can let freezing outdoor air hit the coil and ice it, or pull a partial damper that whistles and starves airflow. In NYC winters this can crack a coil and knock the unit offline during your busiest hours.
Expert Makeup Air Unit Repair for Commercial Kitchens & Buildings
A makeup air unit exists to replace the cubic feet per minute of air your kitchen exhaust hoods pull out of the building. When the MAU stops supplying tempered air, the space goes negative: hood capture fails and smoke rolls into the dining room, entry doors become hard to open, gas appliances backdraft, and the exhaust fans starve and overheat. For a restaurant or commercial kitchen, that means a space you can't legally or comfortably operate. Com+ Mechanical diagnoses and repairs the full MAU system, the direct-fired or indirect-fired burner and its modulating gas valve, the supply blower and motor, the VFD or two-speed control, the discharge air temperature sensor, the high-limit and airflow proving switches, the intake damper and actuator, and the interlock that ties the unit to your hood exhaust fans. We service rooftop and indoor makeup air units from the major commercial manufacturers, restore the exhaust-to-supply balance your hood system was designed around, and verify safe combustion before we leave. Whether you manage one restaurant or a portfolio of foodservice tenants across NYC, we get your makeup air back online so the kitchen can run.
What Our MAU Service & Repair Includes
Why Reliable Makeup Air Matters for Your Building
Our Simple Process
From call to comfort in 4 easy steps
Assess & Measure
We inspect the makeup air unit and measure the real numbers: supply CFM, hood exhaust CFM, building pressure, gas pressure, and discharge air temperature. That tells us exactly how far out of balance the kitchen is and where the fault is.
Diagnose the Root Cause
We trace the problem to the actual failed component, burner and gas train, blower and motor, VFD, dampers and actuator, safety switches, sensors, or the exhaust-fan interlock, rather than guessing or swapping parts blindly.
Repair & Restore Balance
We repair or replace the failed parts, then rebalance supply air against measured hood exhaust so the building returns to slightly negative-to-neutral and the hoods capture properly again.
Verify & Document
We run a full combustion and safety check, confirm the MAU stages correctly with the hoods, and document readings and work performed so you have a record for your files and inspectors.
Types of Systems We Install
Direct-Fired Makeup Air Units
The most common MAU for commercial kitchens. A gas burner fires directly in the airstream for high efficiency, modulating to temper large volumes of outdoor makeup air. We service the burner ribbon/profile, modulating gas valve, ignition, and airflow proving controls.
- •High-efficiency in-airstream gas burner with modulating control
- •Sized to replace high kitchen exhaust CFM
- •Airflow proving and high-limit safeties we test every visit
- •Common on rooftop restaurant ventilation systems
Indirect-Fired Makeup Air Units
Used where a heat exchanger must separate combustion from the supply airstream. We inspect the heat exchanger for cracks, verify draft/inducer operation and flue integrity, and service the controls that keep tempered air flowing safely.
- •Sealed heat exchanger isolates combustion from supply air
- •Heat exchanger crack inspection and flue integrity check
- •Inducer / draft proving diagnosis
- •Common in mixed-use and tenant build-outs needing isolation
Tempered / Heating & Cooling MAUs
Larger makeup air units that both heat and cool incoming air, often with a DX or chilled-water coil plus a VFD-driven supply blower. We service the coil, temperature controls, dampers, and variable-speed drive so the unit delivers conditioned makeup air year-round.
- •Heating plus DX or chilled-water cooling of makeup air
- •VFD-driven supply blower for demand-based airflow
- •Coil and freeze-protection service for NYC winters
- •Integrated with hood demand-control ventilation where present
Why Choose Com+ Mechanical
Commercial Kitchen Specialists
We work on restaurant and foodservice ventilation every day, MAUs, exhaust hoods, and the interlocks that tie them together, not residential furnaces. We understand how makeup air, hood capture, and building pressure depend on each other.
Whole-System Approach
We don't just relight a burner. We measure exhaust versus supply and fix the balance, so the symptom (smoking hoods, doors that won't open) actually goes away and stays away.
NYC Metro Coverage
We serve the five boroughs plus Nassau, Westchester, northern New Jersey, and Stamford, CT, including rooftop MAUs on tight city buildings and back-of-house indoor units.
24/7 Emergency Response
A down makeup air unit can close a kitchen. We offer 24/7 emergency service so a negative-pressure, no-heat, or locked-out MAU gets handled fast.
Transparent Pricing
No fees. No surprises. Just honest service.
MAU Repair & Rebalance
Repair of the failed components and rebalancing of supply air to hood exhaust, restoring capture, heat, and code-compliant operation.
- Burner, gas valve, ignition, blower, motor, VFD, damper, or sensor repair
- Safety control testing and combustion verification
- Supply-to-exhaust airflow rebalancing
- Exhaust-fan interlock / staging restored and confirmed
Planned Maintenance Agreement
Scheduled MAU and kitchen ventilation maintenance to prevent negative-pressure surprises and keep documentation current for inspections.
- Recurring MAU service visits with priority emergency response
- Filter, belt, damper, and burner upkeep before failures start
- Annual combustion and balance check with documented readings
- Portfolio scheduling and reporting across multiple locations
All pricing is scoped after an on-site assessment, since makeup air repairs depend on unit type, size, controls, and how far out of balance the kitchen is.
Own a Commercial Property?
Business+ plans start at $499/year — includes 2 rtu tune-ups, 10% off all services, and priority scheduling.
Equipment & Brands We Service
Factory-trained technicians for all major HVAC manufacturers
%20--%3e%3csvg%20version='1.1'%20id='Layer_1'%20xmlns='http://www.w3.org/2000/svg'%20xmlns:xlink='http://www.w3.org/1999/xlink'%20x='0px'%20y='0px'%20viewBox='0%200%20150%2050'%20style='enable-background:new%200%200%20150%2050;'%20xml:space='preserve'%3e%3cg%3e%3cpath%20style='fill:%23C9202F;'%20d='M124.447,44.322c-23.807,5.229-55.19-0.102-55.19-0.102s73.175,3.979,71.344-20.254%20C138.687-1.368,35.312,8.163,35.312,8.163c60.192-10.521,91.646-0.564,93.939-0.144c11.942,3.18,19.694,9.036,20.404,15.459%20C151.563,35.271,135.269,41.943,124.447,44.322z'/%3e%3cpath%20style='fill:%23C9202F;'%20d='M83.171,38.6c-2.416,0-4.058-0.553-4.927-1.656s-1.022-2.773-0.301-5.027l4.168-12.728%20c0.861-2.684,1.97-4.478,3.324-5.382c1.353-0.904,3.469-1.357,6.35-1.357h2.956c2.877,0,4.145,0.301,5.231,1.535%20c0.934,1.06,0.972,2.521,0.108,5.205l-4.149,12.718c-0.723,2.254-1.507,4.117-3.085,5.223S88.903,38.6,86.488,38.6L83.171,38.6z%20M96.602,18.799c0.302-1.029,0.558-1.979,0.113-2.657c-0.327-0.502-0.804-0.66-1.711-0.731c-0.829-0.117-2.286-0.062-2.286-0.062%20c-1.258,0.037-2.021,0.267-2.65,0.772c-0.629,0.506-0.955,1.038-1.479,2.669L84.19,32.285c-0.406,1.26-0.455,2.143-0.151,2.65%20c0.302,0.506,1.244,0.822,2.747,0.822c1.418-0.004,2.752-0.059,3.935-0.955c0.682-0.43,1.019-1.258,1.459-2.508L96.602,18.799z'/%3e%3cpath%20style='fill:%23C9202F;'%20d='M14.834,38.18c0,0-14.646,0.014-14.643,0.002l8.314-25.357h6.201c0,0-7.508,22.517-7.448,22.517%20h8.521L14.834,38.18z'/%3e%3cpath%20style='fill:%23C9202F;'%20d='M39.008,15.701c-0.006,0,0.945-2.86,0.945-2.86H25.417c-0.002,0-0.005,0-0.005,0l-8.31,25.339H31.61%20l0.951-2.838c0,0-7.745,0-8.385,0c-0.027,0,1.516-4.672,3.201-9.758c3.337,0,7.298,0,7.294,0c-0.008,0,0.938-2.859,0.938-2.859%20s-3.821,0-7.282-0.001c0.876-2.64,1.72-5.18,2.333-7.023C34.597,15.701,39.013,15.701,39.008,15.701z'/%3e%3cpath%20style='fill:%23C9202F;'%20d='M77.25,12.821l-5.508,16.97l-2.311-16.967l-6.073,0.003l-8.253,25.356h6.074l5.537-16.979%20c0,0,2.265,16.725,2.305,16.971l-0.002,0.006l3.525,0.002l8.242-25.363L77.25,12.821L77.25,12.821z'/%3e%3cpath%20style='fill:%23C9202F;'%20d='M121.157,12.821h-4.427l-5.274,6.652l-1.309-6.652l-6.496,0.007l2.393,11.52l-10.54,13.836h4.357%20l7.112-9.356l1.94,9.352l6.226,0.002l-2.777-14.11L121.157,12.821z'/%3e%3cpath%20style='fill:%23C9202F;'%20d='M56.332,12.822l-5.511,16.971l-2.308-16.965l-6.075,0.003l-8.252,25.357h6.074l5.535-16.981%20c0,0,2.268,16.739,2.305,16.97l-0.002,0.012h3.527l8.241-25.365h-3.534L56.332,12.822z'/%3e%3cpath%20style='fill:%23C9202F;'%20d='M138.687,44.271c0,1.305-1.07,2.375-2.376,2.375c-1.305,0-2.373-1.07-2.373-2.375%20s1.068-2.373,2.373-2.373S138.687,42.967,138.687,44.271z%20M134.331,44.271c0,1.076,0.903,1.975,1.979,1.982%20c1.075-0.008,1.981-0.906,1.981-1.982c0-1.074-0.906-1.98-1.981-1.98C135.234,42.291,134.331,43.197,134.331,44.271z%20M135.688,42.98h1.022c0.559,0,0.768,0.295,0.768,0.57c0,0.533-0.334,0.695-0.616,0.834l0.42,1.08l-0.681,0.092l-0.317-1.041%20h-0.288l-0.211,1.004h-0.621L135.688,42.98z%20M136.095,44.135h0.223c0.321,0,0.524-0.189,0.524-0.48%20c0-0.156-0.124-0.295-0.327-0.295h-0.262L136.095,44.135z'/%3e%3c/g%3e%3c/svg%3e)
Don't see your brand? We service all major manufacturers! Call us to confirm.
Proudly Serving Nassau County
Fast, reliable service in your neighborhood
Frequently Asked Questions
Get answers to common questions about our services
How fast can you respond when our makeup air unit goes down?
We offer 24/7 emergency service across the NYC metro because a failed MAU can force a kitchen to close — negative pressure kills hood capture and can backdraft gas appliances. Call (332) 600-4640 and we'll dispatch to get supply air and heat restored.
How do I know if the problem is the makeup air unit or the exhaust hoods?
They work as one system. If the hoods are smoking, doors are hard to open, or the kitchen feels negative, the cause is usually that the MAU isn't supplying enough air to match what the hoods exhaust. We measure both supply and exhaust CFM plus building pressure to confirm whether the fault is in the MAU, the interlock, or the exhaust side, then fix the actual cause.
Why is my MAU blowing cold air into the kitchen?
The blower is running but the burner isn't firing or modulating. On direct-fired units that's commonly a failed ignition module, a faulty modulating gas valve, a tripped high-limit, or a bad discharge air temperature sensor. We test the gas train and controls, repair the fault, and recalibrate the unit so it tempers makeup air to setpoint instead of dumping raw outdoor air on the line.
Do you service makeup air units across multiple restaurant locations?
Yes. We service single restaurants and multi-building portfolios of foodservice tenants across the five boroughs, Nassau, Westchester, northern NJ, and Stamford, CT. We can standardize MAU maintenance and keep documented service records for every location so property managers and operators have one accountable contractor.
Can servicing the MAU help with Local Law 97 and energy costs?
An out-of-balance or stuck-wide-open makeup air unit wastes fuel heating air the kitchen doesn't need and forces the rest of the building to fight the pressure imbalance. Restoring proper modulation, damper control, and exhaust-fan interlock cuts wasted gas and electric load, which supports Local Law 97 emissions goals for covered NYC buildings.
What does a planned maintenance agreement on a makeup air unit cover?
Recurring visits to service the burner, blower, belts, filters, dampers, and controls before they fail, plus an annual combustion and airflow-balance check with documented readings. It means fewer emergency negative-pressure events, predictable budgeting, and inspection-ready records.
Love Our Service? Share Your Experience!
Manage a building we've serviced? A quick review helps other NYC property managers and building owners find us.
5 stars • 500+ reviews
Most Requested Services
Our businesses' top picks for heating, cooling & air quality
Explore Commercial HVAC Resources
Equipment services, industry expertise, NYC compliance, and the metro areas we cover.
Equipment, Repair & Maintenance
Industries We Serve
NYC Compliance & Energy Law
Service Areas
Get Your Makeup Air Unit Back in Balance
Don't let a failing MAU smoke out your kitchen, close a dining room, or rack up emergency calls. Com+ Mechanical repairs your makeup air unit and restores the supply-to-exhaust balance your building depends on — and with a planned maintenance agreement, we keep it that way, with fewer emergencies, predictable budgeting, and inspection-ready documentation across every location. Call (332) 600-4640 or request service to put a commercial kitchen ventilation specialist on it.
Request MAU Service