Keeprite Refrigiration Condensing Unit KMS120L6

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 at the evaporator within the acceptable range of 6 to 10 °F (3.4 to 5.6 °C) for systems with a 10 °F (5.6 °C) design TD?

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 6 inches back from the compressor suction valve

Calculate the actual superheat at the compressor

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

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 contact point 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

Recheck the system for leaks after 12 hours

Verify all electrical and refrigeration connections are tight

Check compressor crankcase oil level (if equipped with sight glass)

Are compressor shipping spacers or hold down nuts properly in place?

Are the compressor discharge and suction shut-off valves open?

Are all pressure controls and safety controls adjusted properly?

Is the room thermostat set for normal operation?