Commercial Unit Heater & Air Curtain Repair & Service in Southern California and Arizona

What equipment does unit heater and air curtain repair cover?

Unit heater and air curtain repair covers the back-of-house and doorway equipment that rarely makes the maintenance scope until it fails: entry and drive-through air curtains, warehouse and loading-dock unit heaters, exhaust fans, and make-up air units.

We repair gas-fired and electric unit heaters, ambient and heated air curtains, and the exhaust and make-up air equipment that keeps a building in pressure balance, across all makes and models. REE Mechanical Inc. is licensed, bonded and insured, and this work is handled by our own technicians on the same terms as rooftop calls.

How does an air curtain work, and why does it fail quietly?

An air curtain blows a controlled sheet of air across a doorway to separate conditioned indoor air from outside air while the door is open. When it fails, nothing alarms; the building simply starts losing cooling at the door.

It only works when it is sized and mounted to cover the full width and height of the opening, and when its door switch tells it to run at the right moments. A weak fan, a failed switch, or a misaimed nozzle can leave the unit humming while doing very little. The first sign is often dust, insects, or outside heat noticeable a few steps inside the entrance.

What is a unit heater, and what goes wrong with it?

A unit heater is a self-contained heater, usually hung from the structure, that uses a fan to push warm air into a dock, stockroom, or warehouse bay. Most failures are in ignition, the gas valve, venting, or the fan motor.

Because these heaters may run only a few weeks a year in Southern California and Arizona, problems tend to show up on the first cold morning: a burner that tries to light and locks out, a heater that blows cold air, or a burning or exhaust smell when it finally fires.

What are the signs this equipment needs repair?

Look for air curtains that do not start with the door, heaters that will not light or cycle off early, odd odors, rattling fans, and doors that whistle, slam, or resist opening.

• Air curtain fans that stay off when the door opens, or airflow too weak to feel at the threshold.
• A unit heater that locks out after repeated ignition attempts.
• Burning, gas, or exhaust odors near a heater. If gas is suspected, clear the area and call the gas utility first.
• Worn belts, squealing bearings, or rattling on exhaust or make-up air fans.
• Entry or back doors that are hard to open or will not close on their own.

When does a back-of-house failure become urgent?

A back-of-house failure becomes urgent when it drives up rooftop unit run time, leaves staff working in a cold dock or stockroom, or pushes the building out of pressure balance.

• A failed air curtain at a main entrance lets conditioned air escape, and the rooftop units run longer trying to make up for it.
• A failed unit heater can leave a dock or stockroom below a safe working temperature.
• A failed exhaust or make-up air unit can unbalance the building, which shows up as doors that will not close and complaints from the sales floor.

We are on call 24/7. Vanny Weber, our Scheduling and Operations Lead, gets these calls on the board like any other, and dock or high-bay work can be timed around deliveries and trading hours.

What does a service visit include?

The visit restores safe operation and correct airflow, then checks the controls that tell the equipment when to run. Each equipment type has its own short list.

Equipment	What the technician checks
Air curtains	Fan motors, wheels, and bearings; door switches; heater elements on heated models; airflow coverage across the opening
Unit heaters	Ignition sequence, gas valve, burners, heat exchanger, venting, limits, fan motor
Exhaust fans	Belts, bearings, motors, dampers
Make-up air units	Heating section, filters, belts, and the interlock with exhaust

Every visit ends with a run test and a note on your work order recording what was found and fixed.

Why should this equipment be on the asset register?

Because equipment that is not on the register is not on the maintenance schedule either. It gets discovered on failure.

Until then, the cost shows up as higher energy use and extra wear on the rooftop units instead of as a work order. Once it is serviced, each air curtain, heater, and fan should enter the asset register and the maintenance rotation alongside the primary equipment. Our guide to building an HVAC asset register shows how to start.

What safety and code points apply to gas-fired heaters?

Gas-fired unit heaters and make-up air units involve combustion and venting, so faults belong with licensed, qualified technicians. Venting, clearance, and permit requirements vary by jurisdiction.

Check local requirements before replacing equipment. When a repair is not the sensible spend, Jessica Bresciani, our Estimating Operations Lead, turns the findings into a quote for replacement. Our guide to make-up air and exhaust balance in retail stores explains how pressure problems show up on the sales floor.

Where do we service unit heaters and air curtains?

Across our full service area: six Southern California counties and the whole of Arizona. See all service areas, including San Bernardino County and Los Angeles County.

Get the back of house looked at

Call (800) 742-0910. If the equipment is past economical repair, see make-up air and exhaust installation and replacement, or add it to a preventive maintenance program.