In this month’s troubleshooting situation, the customer hasn’t called because their HVAC system has stopped cooling. You’re there because they’ve requested a preventive maintenance check of the five-year-old equipment to determine if there are any potential problems that would affect the system performance in the future.

In addition to checking temperature splits and airflow, you are also checking the condition of the system’s electrical components. In the process of checking the dual run capacitor (see the partial diagram in Figure 1), you use your digital ammeter while the compressor is operating to make tests that show the following results:

• When testing the current draw of the blue wire leading from the H terminal on the capacitor to the start winding, your reading is 36.5 amps.

• When testing the current draw of the yellow wire leading to the run winding and the black wire leading to the common terminal of the compressor together, your reading is 34.1 amps.

Your troubleshooting question: What is the next step you need to take in repairing this equipment?

Compare your answer with ours by clicking on the PDF link below.

Publication date: 7/8/2013

PDF - July Troubleshooting Answer

For information on Jim Johnson’s HVACR technician training DVDs, go to

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