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P00177 CHECK EXV (EVXV) SUPERHEAT
• ACTIVATION: With the unit running in Test 11, after the APX 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 CONTROL: Pretrip will fail and display “PRETRIP FAIL AND COMPLETED”.
• RESET CONDITION: Auto reset if Pretrip is started again or alarm may be manually reset using the dis-
play mounted keys or by turning the unit off then back on again.
NOTE: Follow the steps below until a problem is found. Once a repair or correction has been made, clear the
alarm(s). (Refer to Note 1 in Notes Section.) Operate the unit through the appropriate modes to see if any active
alarm occurs. Continue with the steps below as necessary.
CORRECTIVE ACTIONS:
1. Check Refrigerant Level - Check refrigerant charge. Refer to Section 8.5.2.
2. Check System Pressures - Install manifold gauge set and check and compare compressor discharge &
suction pressures with those shown on the microprocessor display. Suction and Evaporator Outlet pres-
sures must be above 3 psig (0.2 bar.) Refer to Section 8.7.11 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 8.7.8.
d. Check basic refrigeration system. Pressures normal. 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. 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 EVAP TEMP SENSOR.
P00179 CHECK LIV
• ACTIVATION: With unit running at the end of Test 13 (ECXV closed, LIV de-energized, SMV set to maxi-
mum position and EVXV controlling normally), the LIV is energized. If the Compressor Discharge Tempera-
ture Delta (Initial Compressor Discharge Temperature – the Current Compressor Discharge Temperature)
does not reach 95°F (35°C) within 70 seconds, it indicates that the LIV is not opening properly.
• UNIT CONTROL: Pretrip will fail and display “PRETRIP FAIL AND COMPLETED”.
• RESET CONDITION: Auto Reset if Pretrip is started again, or alarm may be manually reset via keypad or
by turning the unit off, then back on again.
CORRECTIVE ACTIONS:
Check LIV Circuit - Refer to procedure for alarm 00114 CHECK LIV CIRCUIT.
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