At Fast Affordable Air, we recently completed an HVAC service call on a rooftop system in Las Vegas. The customer reported that their central air conditioning was no longer keeping the house cool. After a thorough diagnostic using a Fieldpiece SC260 meter, we identified the root cause and performed all necessary repairs to restore full system performance.
Initial Inspection and Setup
Once we accessed the rooftop, we visually inspected the Rheem Classic rooftop package unit. This unit handles both heating and cooling. Right away, we checked the condition of the sealed electrical conduit, PVC condensate drain line, and system mounting legs. The unit appeared structurally sound, with properly sealed roof penetrations and no visible refrigerant leaks around the service valves.
There was also a helpful reminder label on the side panel: “Clean coils using water only”. Keeping coils clean is essential because dirty coils reduce heat transfer and force the system to work harder, using more electricity and delivering less cooling.
Electrical and Voltage Testing
We opened the control panel and used a Fieldpiece SC260 multimeter to test incoming voltage. The screen read 120.4 volts AC. That’s well within the normal range for control voltage (usually between 110V and 125V depending on local conditions). Proper voltage is crucial to avoid short cycling or system shutdowns.
We also tested the contactor—this is a small switch inside the unit that sends power to the compressor and fan motor. If this part fails, the whole unit won’t run. All connections were tight, and no burn marks or pitting were found.
System Evaluation and Performance
After confirming proper voltage, we performed a full system run test. This included:
- Listening for unusual compressor noises or fan wobbling
- Checking refrigerant pressure using a gauge set
- Inspecting wiring and connections for heat or corrosion
- Monitoring the outdoor fan and compressor startup
There were no signs of refrigerant undercharge or overcharge. Fan motor and compressor amps were within manufacturer specs. This is important because motors that pull too much power could indicate wear or overloading.
Benefits of This Repair
This rooftop unit is now running smoothly. By catching electrical issues early, we helped prevent compressor failure, which is much more expensive to repair. The system is now able to deliver proper cooling performance and comfort, especially during hot Vegas afternoons.
Because we confirmed safe electrical operation, proper drainage, and refrigerant charge, the customer should now see improved efficiency and lower energy bills. When your system doesn’t have to struggle to work, it naturally saves money and lasts longer.
For similar rooftop system repairs, we always recommend regular maintenance and full diagnostic checks. You can learn more about our air conditioning repair services or preventive maintenance options to keep your system running strong year-round.
