Commercial Furnace Repair in Ontario, CA

Expert Repairs for Rooftop and In‑Building Heating Systems

Downtime hurts productivity. Our commercial technicians zero in on the root cause fast—whether it’s ignition failures, cracked heat exchangers, faulty gas valves, blower motor issues, control board errors, sensor/limit switch faults, or airflow and duct problems. We service gas and electric furnaces, rooftop package units (RTUs), make‑up air units, and associated ventilation components across offices, warehouses, retail, restaurants, healthcare, education, and more.

Factory‑Trained Skill, Real‑World Results

Our engineers have trained at manufacturer facilities including Fujitsu (Japan), Mitsubishi Electric (Thailand), Midea (China), Gree (China), and Haier (China). That depth of training—combined with 80+ years of family engineering experience—means faster diagnostics, smarter repairs, and longer‑lasting results. We service all major commercial brands and integrate repairs with your existing controls and building management systems.

Safety, Compliance, and Performance

We repair to California codes and best practices, emphasizing combustion safety, proper venting, gas line integrity, and carbon monoxide risk reduction. Every repair includes operational testing, temperature rise checks, combustion/airflow verification, and control calibration. The outcome: safer operation, lower utility waste, and consistent heat across your zones.

Common Commercial Furnace Repairs We Handle

• Ignition and pilot assembly service (hot surface, spark, intermittent pilot)
• Heat exchanger inspection and replacement planning
• Blower motors, bearings, belts, and VFD troubleshooting
• Gas valves, pressure regulators, and manifold adjustments
• Control boards, relays, sensors, and safeties
• Economizer and ventilation integration on RTUs
• Short‑cycling, lockouts, and uneven heating issues
• Duct leaks, airflow balancing, and filtration upgrades

Proactive Maintenance to Prevent Breakdowns

After we restore heat, we can set up a customized maintenance plan: seasonal tune‑ups, filter and belt schedules, coil and burner cleaning, combustion checks, and documentation for compliance. Routine care reduces emergency calls, improves indoor air quality, and extends system life.

Transparent Process, Minimal Disruption

1) Rapid dispatch and on‑site assessment in Ontario, CA
2) Clear findings and a written estimate before work starts
3) Code‑compliant repair with quality parts
4) System testing and balancing for reliable heat
5) Clean jobsite and recommendations to prevent recurrence

Built for Big and Complex Projects

As a 4th‑generation family business, we’ve grown by solving tough problems. Multi‑unit properties, large warehouses, distribution centers, and mixed‑use buildings are where we thrive. Need staged repairs, night or weekend work, or coordination with facility teams? We’ve got you covered.

Healthy Indoor Air for a Healthier Workplace

Our mission is healthy air for healthy lives. We address ventilation, filtration, and circulation to support cleaner indoor environments—vital for comfort, safety, and productivity. Ask about IAQ improvements, better filtration, and airflow balancing during your repair visit.

Proudly Serving Ontario, CA and Surrounding Areas

We support Ontario and nearby Inland Empire communities, along with Los Angeles County and adjacent regions including Orange County, Ventura County, and Western Riverside County. If you’re near the county line or have multiple sites, our dispatch team will coordinate efficient coverage.

Why #1 AC Guys

• 4th‑generation, family‑owned integrity
• 80+ years of engineering problem‑solving
• Factory‑trained technicians for advanced systems
• Fast, reliable response with 24/7 emergency service
• Transparent pricing and workmanship you can trust

Get Your Heat Back—Today

Don’t let a furnace outage disrupt your business. Contact #1 AC Guys for same‑day commercial furnace repair in Ontario, CA. We’ll restore safe, efficient heat, protect your bottom line, and keep your people comfortable.