A Central AC Compressor Replaced to Restore Cooling in Chicago

A Rooftop AC That Would Not Cool in Chicago

A customer in Chicago called A+ Appliance Repair and Maintenance about an outdoor central air conditioning condensing unit, mounted on the roof, that was not cooling properly. A central AC that has stopped cooling in summer is an urgent comfort problem, and this one turned out to need the most significant sealed-system component replaced: the compressor. The repair is a good example of doing that job the right way, by the book.

What the diagnosis found

Upon diagnosis, the compressor was found to have an internal mechanical failure and was no longer pumping refrigerant through the system. The compressor is the pump at the heart of an air conditioner, it circulates the refrigerant that actually moves heat out of the home. When it fails mechanically and stops pumping refrigerant, the system loses its cooling entirely, even if other parts still run. So a failed compressor meant compressor replacement was required to restore cooling.

Doing the sealed-system work correctly

Replacing an AC compressor is a serious sealed-system job, and it was done thoroughly. Our technician recovered the remaining refrigerant from the system and removed the failed compressor, then installed a new OEM Copeland compressor along with a new liquid-line filter drier. All the refrigerant connections were brazed while flowing nitrogen through the lines, a professional practice that prevents internal oxidation and contamination inside the tubing during brazing. After installation, the sealed system was pressure-tested with 350 psi of nitrogen, and it held pressure with no significant loss, confirming there were no refrigerant leaks. The system was then evacuated with a high-capacity vacuum pump down to a deep vacuum, which removes moisture and non-condensable gases from the sealed system, an essential step for reliable operation. Finally, the factory-specified charge of R-410A refrigerant was weighed into the system.

Each of those steps matters. Leak-testing, deep evacuation, brazing under nitrogen, a new filter drier, and a weighed factory charge are what separate a compressor replacement that lasts from one that fails again, and they were all part of this repair.

Verified and running properly

After the charge, the unit was started and tested for proper operation. The refrigerant pressures, superheat and subcooling, compressor amperage, and temperature split were all verified and found to be within normal operating range, and the system was operating properly with no additional issues found. Taking those readings is how you confirm the system is not just running but running correctly and efficiently, which is the true measure of a completed AC repair.

About A+ Appliance Repair and Maintenance

We handle cooling and appliance repairs throughout Chicago and the surrounding communities, including full sealed-system and compressor work performed to proper standards. Our technicians are certified for refrigerant work.

We quote the price upfront before any work begins, we waive the service call fee when you move forward with the repair, and we stand behind our work. If your central AC has stopped cooling, we can diagnose it and, when needed, perform a proper compressor and sealed-system repair to get it cooling again.