Commercial Split System Installation & Replacement in Southern California and Arizona

What makes a split system project different from a rooftop unit?

A split system has two halves in two places, joined by refrigerant piping. The condensing unit sits on a roof, pad, or mezzanine; the air handler sits indoors. Both halves, and the lines between, shape the job.

REE Mechanical Inc. installs and replaces commercial split systems up to 60 tons. The indoor half is usually the part that surprises people. It may sit in a mechanical room that later remodels walled in, or above a finished ceiling under years of cable and sprinkler work. For the trade-offs between the two configurations, see packaged vs split systems in commercial buildings.

When does a building call for a new split system?

When a space needs cooling the existing equipment cannot supply and a rooftop unit is impractical: an interior tenant space without roof access, a roof that cannot take the weight, or an expansion beyond the original design.

New installs start with a load review of the space as it will be used, not as it was first drawn. A tenant improvement that adds fitting rooms, or a change of use that brings in more people, can push the load past what the original design assumed. Where both halves will go, how the line set will run, and where condensate will drain should all be on the drawings before anyone picks equipment.

Is it worth replacing the whole system rather than one half?

Usually, when the failure is major and both halves are the same age. Outdoor sections weather while indoor sections look fine, tempting owners to replace only the outdoor half. A new condenser on an old coil may underperform.

Situation	Repair is reasonable	Replace both halves
What failed	Fan motor, contactor, controls, a minor leak	Compressor or coil on an aging system
Refrigerant	Current and available	Phased down, with recharge cost climbing
Indoor section	Newer and in good condition	Same age as the failed outdoor unit
Load	Unchanged since install	The space or its use has changed

Why do line sets and controls decide so many split system jobs?

Because they are carried over from the old system. Old refrigerant lines can hold oil and contaminants a new refrigerant will not tolerate, and new equipment often cannot talk to a legacy thermostat without integration work.

A line set should be evaluated, then flushed or replaced to suit the refrigerant going in; reusing it untreated invites a repeat failure. On the controls side, we install and service controls ourselves, so the new system can report into whatever your team already monitors. For the refrigerant picture across a portfolio, read the refrigerant transition: what facility managers need to track.

How is a split system change-out sequenced?

Survey both halves, choose a matched pair, plan both access paths, then remove, set, pipe, and start up. The steps below are typical for a commercial change-out.

1. Walk the outdoor and indoor locations, the structure under each, and both removal paths.
2. Select a matched condensing unit and indoor section for the actual load.
3. Evaluate the line set against the new refrigerant.
4. Pull the permit. Kelly Purcell, who directs our installations, treats permitting as her specialty; in California the issuing office is usually the city.
5. Plan the crane or rigging for the outdoor unit and the interior access for the indoor one.
6. Recover refrigerant and remove the old equipment.
7. Set, pipe, evacuate, charge, and connect condensate and power.
8. Integrate controls, start up, and update the asset register.

How do you plan split system work across many sites?

Document the indoor halves before you need them. Across a portfolio, the outdoor units are easy to count from the roof; the air handlers above ceilings and in back rooms are the ones missing from inherited records.

Record both halves for each system, with age, refrigerant, and repair history, so phased-down systems rise to the top of the list. Note the ceiling or mechanical room access for each one. Confirm lead times before promising a tenant a work window, and schedule indoor work around occupied hours.

What affects the scope of a split system project?

Tonnage and the number of indoor sections, line set length and condition, where each half sits, how each half gets in and out, electrical and condensate changes, controls integration, and the work windows the building allows.

A rooftop condenser over an open warehouse is a simple pick. The same condenser serving an air handler above a finished office ceiling is a different job, because the indoor work sets the schedule. That is why both halves get surveyed before a quote is written.

Who installs REE Mechanical’s split systems?

Our own installation team, led by Install Foreman Anthony Renteria. REE Mechanical Inc. self-performs split system work with factory-trained, EPA-certified technicians and is licensed, bonded and insured.

If replacement equipment is delayed in the middle of summer, temporary cooling through our Herc Rentals relationship can hold a Southern California space until the new system is running.

Where does REE Mechanical install split systems?

From Ventura County down to San Diego County, and throughout Arizona. See Los Angeles County, San Diego County, or all service areas.

How do you get a split system project scoped?

Call (800) 742-0910 with the site and the system tonnage if you have it. Related pages: rooftop unit installation and replacement, ductless mini-split installation and replacement, and preventive maintenance for systems that are not due yet.