Commercial AHU (Air Handling Unit) Repair in Fullerton, CA

Your commercial AHU is the heart of building airflow, pressurization, and indoor air quality. When something is off—temperature swings, poor ventilation, rising energy bills, or unusual noise—#1 AC Guys brings an engineer‑level approach to find root causes and fix them right the first time.

What we repair on commercial AHUs

• Supply/return fans, fan arrays, motors, bearings, shafts, belts, and pulleys
• Variable frequency drives (VFDs), contactors, and motor starters
• Coils (chilled/hot), fin damage, refrigerant or hydronic issues, and condensate drain pans
• Economizers, outside air dampers, actuators, linkages, and seal kits
• Filters and frames, MERV upgrades, prefilter/final filter retrofits
• Sensors (temperature, humidity, pressure) and freeze stats
• Control boards, safeties, BAS integration, and communication faults
• Energy recovery wheels (ERV), enthalpy controls, and heat sections
• Cabinet leakage, access doors, and insulation repairs

Engineer‑led diagnostic process

We approach every commercial AHU repair with a structured method to reduce downtime and avoid repeat failures.

• Interview and trend data: Occupant complaints, schedules, and BAS trends
• Airside testing: Static pressure, airflow, and leakage checks
• Electrical and controls: VFD diagnostics, safeties, sensor calibration, wiring
• Mechanical: Bearings, alignment, belt tension, motor load, vibration
• Heat transfer and condensate: Coil ΔT, fouling, drain pan slope and biofilm
• Ventilation and economizer: Outside air setpoints, damper operation, IAQ balance
• Final commissioning: Verification under load and documentation for your records

The result is a clear, prioritized plan: what to fix now, what to schedule, and what to monitor for reliability and energy savings.

Healthier indoor air is our mission

Our core mission is healthy air for healthy living—and that extends to your business. Better filtration, accurate ventilation, and clean coils reduce irritants, odors, and downtime while improving comfort and productivity.

• MERV filtration upgrades with proper static pressure management
• Coil cleaning and drain remediation to control biofilm and odors
• Outside air and economizer optimization for real‑world conditions
• Sensor calibration to prevent over/under‑ventilation

We balance air quality with energy performance, helping your AHU meet California code expectations while keeping operating costs in check.

Factory‑trained for complex systems

Our team is factory‑trained at Fujitsu (Japan), Mitsubishi Elektrik (Thailand), Midea (China), Gree (China), and Hier (China). Combined with 80+ years of family engineering experience across four generations, we thrive on large and complex commercial AHU projects, from multi‑zone VAV and DOAS to integrated BAS strategies. We service multi‑brand AHU installations and tailor repairs to your specific sequence of operations.

Industries we serve in and around Fullerton

• Office and mixed‑use buildings
• Healthcare clinics, labs, and life‑science spaces
• Education and campus environments
• Retail, grocery, and hospitality
• Light industrial and manufacturing
• Houses of worship and community spaces

Whether it’s restoring airflow on a single large AHU or stabilizing a campus of air handlers with varying vintages, we deliver durable, standards‑aligned solutions.

Service coverage and response

We are based in Southern California and proudly serve Fullerton and all of Orange County, with extended coverage across Los Angeles County, Ventura County, and Western Riverside County. Dispatch is coordinated to minimize downtime and align with building access requirements.

Transparent findings and options

You receive a concise report that documents test results, photos, and recommendations. We explain immediate safety or reliability risks, offer repair pathways that respect budgets and timelines, and can coordinate with your facilities team or property manager.

Why #1 AC Guys

• 4th‑generation family of engineers with 80+ years of engineering expertise
• Factory‑trained at Fujitsu (Japan), Mitsubishi Elektrik (Thailand), Midea (China), Gree (China), and Hier (China)
• Specialists in complex commercial AHU diagnostics and repairs
• Health‑focused approach to indoor air quality and ventilation
• Clear communication, documented results, and practical solutions

If your Fullerton facility’s AHU is noisy, inefficient, or failing to meet ventilation targets, we can help. From VFD faults and actuator failures to coil and drainage issues, #1 AC Guys provides the engineered repair your building deserves—so occupants breathe better and your operation runs smoothly.

Request your commercial AHU repair

Contact #1 AC Guys to schedule diagnostics for your Air Handling Unit in Fullerton, CA. We’ll confirm scope, access windows, and safety requirements, then deliver fast, accurate repairs that keep your building healthy and productive.