The first cold snap in Southeast Wisconsin is the worst time to find out a rooftop unit won't light. Every October, service calls spike as buildings switch from cooling to heating and equipment that sat idle all summer is suddenly asked to run around the clock. Most of those calls are preventable with a structured fall tune-up.
At BREDAN Mechanical Systems, our service technicians follow a consistent checklist on commercial furnaces, gas-fired rooftop units (RTUs), and make-up air units before heating season. Here is what that process covers – and why each step matters.
Why Fall Is the Right Time
Scheduling heating maintenance in September or early October gives your facility time to order parts, plan repairs, and avoid the emergency premiums that come with a no-heat call in January. It also lets technicians catch summer-season damage – storm debris, bird nests, failed condensate drains, and loose panels – before it becomes a heating-season failure.
The BREDAN Fall Tune-Up Checklist
Burners & Ignition
- Inspect and clean burners and burner orifices
- Verify hot surface igniter or spark ignition operation
- Clean and test the flame sensor
- Confirm proper flame pattern and color
Heat Exchanger Inspection
A cracked heat exchanger can allow combustion gases into the airstream. Our technicians visually inspect heat exchangers for cracks, corrosion, and hot spots, and perform combustion analysis to confirm safe operation.
Combustion Analysis
- Measure CO, CO2, O2, and stack temperature
- Adjust gas pressure to manufacturer specifications
- Verify draft inducer motor operation and venting integrity
Safety Controls
- Test high-limit and rollout switches
- Verify pressure switch operation
- Confirm gas valve shutoff and flame safeguard response
Airflow & Filtration
- Replace filters and check filter racks for bypass
- Inspect blower wheel, belts, pulleys, and bearings
- Lubricate motors where applicable
- Verify economizer dampers close fully for winter operation
Controls & Building Automation
- Calibrate thermostats and space sensors
- Confirm heating setpoints and occupancy schedules in the BAS
- Verify staging and modulation sequences
Roof-Level Items
- Check curb seals and unit panels for water and air leaks
- Clear debris from intakes and flue outlets
- Inspect gas piping, unions, and shutoff valves on the roof
Common Problems We Find in the Fall
On Waukesha and Milwaukee County rooftops, the most frequent issues we uncover during fall tune-ups include failed flame sensors, cracked igniters, economizers stuck open, worn blower belts, and nests blocking flue or combustion air openings. Each of these is a small repair in October – and an emergency call in February.
Make-Up Air and Unit Heaters
Don't forget the equipment that only runs in winter. Make-up air units, gas-fired unit heaters in warehouses and loading docks, and infrared heaters in shops all benefit from the same burner, ignition, and safety inspection.
Schedule Your Fall Tune-Up
BREDAN Mechanical Systems provides commercial and industrial HVAC service throughout Waukesha, Milwaukee, Kenosha, Racine, Washington, Ozaukee, and Jefferson counties. Our preventive maintenance agreements include fall heating inspections, priority scheduling, and detailed reporting on every unit. Contact our service team to get your rooftop units and furnaces ready before the first freeze.
