Outdoor unit dead, compressor failure confirmed after checks

What we found

We worked through every external component before testing the compressor itself.

• Run capacitor tested within 5% of rated value — within range, not the cause
• Relay contacts were clean and closing correctly — relay ruled out
• Manual start tried — compressor drew high current and tripped within three seconds
• Winding tested at all three posts — one phase showed open circuit

One coil winding had failed inside the compressor. The coil had broken down after 12 years of use. No external part was at fault.

What we did

The coil failure is inside the compressor and can't be fixed on-site. A swap is possible but costly on a 12-year-old unit. We laid out both options clearly so the customer could decide.

The customer chose a new unit after seeing the costs. We wrote up the test results so they had a clear record of what was checked.

What we learned

Confirming compressor failure vs. relay or capacitor fault.

• A capacitor or relay fault causes clicking or humming. The compressor tries to start but can't spin. The motor itself is still intact.
• Compressor failure looks different: the unit hums briefly then trips, or the outdoor side goes silent.
• The final test is a winding check at all three posts. An open reading means the coil has failed inside. No external part can fix that.
• Age matters too. A 12-year-old unit has run a long time. Repair cost often gets close to new unit cost at that stage.