Commercial HVAC Controls Repair & Service in Southern California and Arizona

What does HVAC controls repair and service cover?

HVAC controls repair and service is troubleshooting and repair of the controls on each piece of equipment: thermostats, space and duct sensors, unit controllers, economizer controls, and the link from each unit to the site’s head end.

We service and repair the controls already in the field on rooftop units up to 100 tons, split systems up to 60 tons, and zone equipment, including controls we did not put in. New controls and work on the head end itself are covered under building management system installation and replacement.

Who handles controls repair at REE Mechanical?

Eric Choi, our Field Service Manager, is our controls lead, and controls service calls run through him.

Meet Eric Choi. REE Mechanical Inc. is licensed, bonded and insured, and our technicians are factory-trained.

When do you need controls service instead of an equipment repair?

Call for controls service when the unit itself checks out but the space still will not behave: a blank thermostat, a room that misses setpoint, a sensor reading wrong, or equipment running outside its schedule.

A remodel, rebrand, or change in trading hours is also a trigger. So is a site whose units have dropped off the head end, so their alarms no longer reach anyone.

What are the most common controls service problems?

Most calls trace back to five causes: drifting sensors, lost programming, dropped communication with the head end, overrides left in place, and wiring disturbed during other work.

• Sensor drift. A sensor a few degrees off makes the unit run too long or not long enough.
• Lost programming. A power interruption or replaced thermostat can reset schedules to factory defaults.
• Communication loss. A unit that drops off the head end keeps running, but its alarms go unseen.
• Leftover overrides. A temporary setpoint change after a complaint quietly becomes permanent.
• Remodel damage. Ceiling and wall work can cut control wiring or move sensors to poor spots.

Where should a space sensor go?

Put it where it reads the space people actually occupy: away from doors, direct sunlight, supply diffusers, and heat-producing equipment such as displays or registers.

A sensor beside an entry door reads every gust of outside air, and one under a supply diffuser reads the unit’s own discharge. Either can make a healthy unit look broken. Sensor placement deserves another look after any remodel, because fixtures and walls move while the sensor often stays put.

What does a controls repair and service visit include?

A controls service visit traces the fault, repairs or replaces what failed, restores the programming to fit the site, confirms the unit reports to the head end, and tests the full sequence before the work order is closed.

1. Confirm the unit itself runs, so the fault is pinned on the controls rather than the equipment.
2. Recalibrate or replace drifting sensors, and replace failed thermostats or controllers.
3. Restore occupancy schedules from real trading hours, holidays, and delivery times.
4. Reset setpoints, limits, and override rules so overrides time out instead of sticking.
5. Check economizer controls and confirm the dampers travel correctly.
6. Confirm the unit reports to the existing head end and every point comes through.
7. Run a functional test of the full sequence and record the settings on the work order.

Service visits are scheduled around trading hours and reported through your IVR or work-order system, the same as any other visit.

What helps a controls service call go smoothly?

Send the site’s current trading hours, any recent remodel or schedule change, and what the store is experiencing and when. With controls faults, timing is often the clue that matters most.

If the site has a head end, note whether the unit still shows up on it and which alarms, if any, have come through. Wiring diagrams, point lists, or as-built drawings help too; when they are missing, the technician has to rebuild that picture on site before the real troubleshooting starts.

Which codes apply to controls work?

Controls on new or altered systems must meet local building and energy codes. California’s Title 24 includes controls requirements for many of these systems; check current code and manufacturer guidance when a repair turns into a replacement.

Where is HVAC controls repair and service available?

Our controls work reaches the same six Southern California counties we cover for service, plus all of Arizona. See all service areas, including Riverside County and Ventura County.

Book HVAC controls repair for your sites

Call (800) 742-0910 or send us the site and the fault. If the unit itself has failed, see commercial AC repair and service; for new equipment, see rooftop unit installation and replacement or the HVAC controls and BMS overview.