The scroll compressor can not be pumped down to check the efficiency of the compressor. Use the following procedure.
This procedure checks loss of cooling capacity at low box temperatures.
1. Install a calibrated gauge manifold per “Installing and Purging
a Gauge Manifold with Low Loss Fittings” on page 12.
2. Run the unit in high speed cool for five minutes or more until pressures stabilize.
3. Note the discharge pressure on the high pressure gauge.
4. Cover the condenser to build discharge pressure.
5. Allow discharge pressure to rise to at least 100 psig above the previously noted pressure.
6. The compressor is probably faulty if it does not raise discharge pressure at least 100 psig. Check all other possible causes of capacity loss before replacing a compressor.