Keeprite Refrigiration Condensing Unit KMS120L9

Compressor Superheat Measurement

Measure the suction pressure at the suction service valve of the compressor

Determine the saturated temperature from the Pressure-Temperature chart

Measure the suction temperature of the suction line

Calculate the actual superheat at the compressor

System Balancing and Adjustment

Is the superheat within the range of 20 to 45 °F (11.2 to 25.2 °C)?

Describe any adjustments made to the suction superheat

Measure the suction pressure in the suction line at the bulb location using a gauge in the external equalizer line or directly in the suction line.

Measure the temperature of the suction line at the point where the thermostatic expansion valve bulb is clamped.

Temperature Conversion and Calculation

Convert the measured suction pressure to a saturated evaporator temperature using a Pressure-Temperature chart.

Subtract the saturated temperature from the actual suction line temperature to find the superheat at the evaporator.

Is the superheat within the acceptable range for the system's design TD?

Disconnect and lock off the main power supply to avoid accidental start up of the equipment.

Check electrical components and tighten any loose connections.

Check all wiring and electrical insulators.

Check contactors for proper operation and inspect contact points for wear.

Are the fan motors operational?

Ensure fan blades are tight and all mounting bolts are secure.

Pressurize the system to a maximum of 150 psig (1136 kPa) with dry nitrogen

Is the system free of major leaks?

Detailed Leak Testing for A1 Refrigerants

Discharge the initial dry nitrogen charge and add refrigerant to raise the system pressure up to 10 psig (170 kPa)

Add dry nitrogen to increase the system pressure to a maximum of 150 psig (1136 kPa)

Use an electronic leak detector to check for leaks

Hold the pressure for a minimum of 12 hours and then recheck

Detailed Leak Testing for A2L Refrigerants

Enter the compressor discharge pressure

Enter the compressor suction pressure

Are the compressor pressures within allowable design limits?

Check the liquid line sight glass and expansion valve operation

Is there an indication of low refrigerant in the system?

Check the system for leaks if low refrigerant is indicated

Enter the oil level in the compressor sight glass

Is additional oil needed in the compressor?