Fujitsu Compressor Test Instructions:

You will need a meter that can do at least 10 Mega Ohms....

Verify you are you using the right scale.

1. Follow the steps carefully.

2. Test for a grounded compressor:

   • Measure resistance (ohms) from each winding (U, V, W) to ground.

   • The reading should be at least 10 megaohms or OL (open line).

   • If the reading is less than 10 megaohms, the compressor is grounded and needs replacement.

3. Test winding-to-winding resistance:

   • Measure resistance between windings: U-V, V-W, and W-V.

   • The reading should be around 1 ohm and be same same value +/- 0.1 ohms.

   • Typically these reading will be from .68-.97 ohms depending on compressor and temperature. If you are seeing reading 2-3 times higher, you may have to get a little history on the units maintenance. Poor running conditions could have caused motor winding damage due to oil loss or liquid flood back. Though it may not be tripping the breaker, it will be a good warning to the homeowner that compressor replacement may come sooner than later.

If readings are outside these ranges, further troubleshooting may be needed.

Here is a video detailing this test sequence.