Check EXV (EVXV) Superheat
refrigeration
Description
Test 11 found the EVXV not closing to 0% properly or evaporator pressure not dropping as required; pretrip fails and shows “PRETRIP FAIL AND COM- PLETED”.
Activation Conditions
With the unit running in Test 11, after the control system closes the EVXV to 0%, evaporator pressure fails to drop by 20 psig (1.36 bar) or fails to go below 0 psig / bar OR the EVXV appears not to be opening to the full capacity position.
Unit Behavior
Engine and Electric Operation: Pretrip will fail and display “PRETRIP FAIL AND COM- PLETED”.
Reset Conditions
Auto reset if Pretrip is started again or alarm may be manually reset using the display mounted keys or by turning the unit off then back on again.
Corrective Actions
1. Check Refrigerant Level - Check refrigerant charge. Refer to Section 8.7.2. 2. Check System Pressures Install manifold gauge set and check and compare compressor discharge and suction pressures with those shown on the microprocessor display. Suction and Evaporator Outlet pressures must be above 3 psig (0.2 bar.) Refer to Section 8.9.11 for instruction on comparison. 3. Check EVXV a. Visually inspect EVXV for damage. Check to see if coil is seated on valve properly. b. Inspect EVXV coil and wire connections. Verify there is no physical damage to harness, and no damage, moisture, or corrosion in connectors. c. Check EVXV operation. See Section 8.9.8. d. Check basic refrigeration system. Verify pressures normal and Compressor operation normal. e. Check the EVXV electrical system for good continuity in all circuits from microprocessor to EVXV. f. Inspect component and wire connections. Verify no physical damage to harness. g. Inspect harness connector pins. Verify there is no damage, moisture, or corrosion in connectors. (See wiring schematic Section 10.3.) 4. Check EVOT - Check the sensor. Refer to procedure for alarm 00131 Check Evaporator Outlet Temperature Sensor.