Central Comfort Ltd. provides commercial make-up air unit repair and service in Calgary and Southern Alberta, including troubleshooting, preventive maintenance, replacement and installation.
When a make-up air unit (MUA) stops heating, delivers too little air or shuts down intermittently, the effect can extend beyond room temperature. Restaurants, warehouses and commercial buildings depend on make-up air to replace exhausted air and support the intended ventilation balance.
We help property managers, building owners and general contractors assess the problem, understand repair options and plan work around the building’s operating needs.
Monday–Sunday, 7:00 AM–9:00 PM.
Commercial MUA Repair & Troubleshooting
A make-up air complaint may involve the unit itself, its controls or its relationship with the exhaust system. We diagnose the installed equipment and its operating sequence before recommending repairs.
- MUA running but supplying cold air
- Burner not lighting or failing to stay lit
- Intermittent shutdowns or repeated lockouts
- Low or inconsistent supply airflow
- Supply fan not starting
- Unusual fan noise or vibration
- Dampers not opening as expected
- Temperature-control or sensor problems
- Operation that does not follow exhaust demand
- Building pressure complaints associated with ventilation
Tell us when the issue occurs, which areas are affected and whether the exhaust equipment is operating. Equipment model information, service history and any displayed fault message help us prepare for the visit.
MUA No Heat, Ignition Failure & Intermittent Shutdowns
A fan can run without a call for heat, and a burner may be prevented from starting by an unmet operating condition. Diagnosis follows the manufacturer’s sequence for the specific unit, including demand, damper and fan operation, relevant proving devices, ignition and flame supervision.
Depending on the equipment, the assessment may involve temperature sensors, heating enable settings, ignition components, flame-safety controls, gas controls, wiring and limit devices. Intermittent faults require attention to the conditions present when the unit stops, rather than repeated resets alone.
Our service addresses the cause of a shutdown and verifies the affected operation after repair. Gas and safety-control work is professional service; safety devices and interlocks must remain functional.
Direct-Fired & Indirect-Fired Make-Up Air Units
Direct-Fired Equipment
Direct-fired units heat the supply airstream at the burner. Airflow through the burner section is part of correct operation, so fan, damper and airflow-proving issues can be connected to heating faults. Assessment follows the unit’s approved configuration and manufacturer requirements.
Indirect-Fired Equipment
Indirect-fired units transfer heat through a heat exchanger, keeping combustion products separate from the supply air. Service considers the heating section, heat-exchanger condition and venting or combustion-air arrangement, as applicable to the installed unit.
The two designs have different operating requirements. We identify the equipment type before choosing diagnostic checks or discussing a replacement.
Airflow, Fans, Belts, Dampers & Controls
Low airflow is not always a motor failure. A service assessment may include intake and filter restrictions, fan condition, belts and bearings where fitted, damper travel, actuators, motor controls and variable-speed drives where installed.
For a system connected to kitchen or process exhaust, the review also considers the relevant exhaust enable signals, fan proving and other installed interlocks. Airflow and building-pressure concerns are assessed in the context of the connected systems; changing one fan’s operation can affect the overall balance.
Preventive Maintenance for Make-Up Air Units
Maintenance is planned around the equipment, operating hours and site conditions. A restaurant kitchen and a lightly used warehouse can have different service needs.
- Filter and outdoor-air intake inspection
- Fan, belt, bearing and motor checks where applicable
- Damper and actuator inspection
- Heating and ignition-system inspection
- Control, sensor and safety-operation checks
- Heat-exchanger and venting inspection on applicable units
- Relevant operating readings and functional testing
- Documentation of deficiencies and recommended work
Service records help property managers track recurring faults and prioritize repairs across multiple units or properties. We can discuss a maintenance scope based on your installed equipment.
Repair Versus Replacement
An isolated fault in an otherwise sound unit may justify repair. Repeated failures, major deterioration, unavailable parts or equipment that no longer suits the ventilation requirement may make replacement worth evaluating.
We consider equipment condition, repair history, parts availability, current repair scope and building needs. Age alone does not determine the recommendation. For indirect-fired equipment, heat-exchanger condition is also relevant to the assessment.
MUA Replacement & Installation Planning
A replacement should be selected for the application, rather than by matching the old unit’s physical size alone. Planning considers required outdoor airflow, exhaust operation, heating demand, the appropriate equipment type and the controls needed for the intended sequence.
Site review may include roof curb or support arrangements, duct connections, service access, lifting access, gas and electrical requirements, controls coordination and applicable permit or design requirements. Building owners and general contractors can use this review to establish the installation scope and required coordination before work begins.
Start-up and operational checks need to address the installed unit and its interaction with the connected ventilation systems.
MUA Service for Commercial & Industrial Buildings
Restaurants & Commercial Kitchens
Make-up air and exhaust operation are considered together when investigating cold supply air, poor airflow or ventilation complaints. See our commercial kitchen HVAC services.
Warehouses & Industrial Facilities
Repair and maintenance for equipment supplying replacement air to spaces with general or process exhaust, with attention to the installed controls and operating schedule.
Property Managers & Building Owners
Equipment assessments, maintenance planning and repair recommendations for commercial, retail and multi-tenant properties across Calgary and Southern Alberta.
General Contractors
Make-up air installation and replacement planning, including equipment selection considerations and coordination with the project’s other building systems.
Frequently Asked Questions
Why is my make-up air unit blowing cold air?
The unit may not have a heating demand, or a control, airflow, ignition or safety condition may be preventing heat. The answer depends on its configuration and operating sequence. A diagnostic visit determines which condition applies.
Does a burner that will not light need a new ignition control?
Not necessarily. The ignition control is one part of the sequence. Demand, airflow proving, interlocks, ignition and flame supervision must be assessed before deciding which component needs repair.
Is a make-up air unit the same as an RTU?
A MUA supplies replacement air for exhausted air. A typical rooftop HVAC unit conditions a building or zone and may use a mixture of outdoor and return air. Their roles and controls differ. For rooftop heating and cooling issues, see our commercial RTU repair and service in Calgary.
Can an exhaust problem affect make-up air operation?
Yes. Connected controls and interlocks can link their operation, and an imbalance between supplied and exhausted air can contribute to building-pressure complaints. The installed system needs to be assessed as a whole.
How often should a MUA be maintained?
The interval depends on manufacturer guidance, operating hours, filter loading, site conditions and service history. Contact us to discuss a schedule for your equipment.
What should I provide when requesting service?
Provide the site address, equipment model if available, symptoms, displayed faults, when the problem occurs and access arrangements. Mention related exhaust problems and any recent service or changes to the system.
Do you provide MUA replacement and installation?
Yes. Central Comfort provides make-up air installation and replacement services. An equipment and site assessment helps establish the appropriate scope.
Explore our make-up air, rooftop unit and exhaust fan equipment overview for the roles of these systems.
Request Commercial Make-Up Air Service
For MUA repair, troubleshooting, maintenance or replacement in Calgary and Southern Alberta, contact Central Comfort Ltd.
Monday–Sunday, 7:00 AM–9:00 PM.
