Check Comp Discharge Sensor
refrigeration
Description
Compressor Discharge Temperature Sensor is out of -40° to +392°F (-40° to +200°C), and the unit only alarms.
Activation Conditions
Compressor Discharge Temperature Sensor (CDT) is not within the range of -40° to +392°F (-40° to +200°C).
Unit Behavior
Alarm Only.
Reset Conditions
Auto reset when sensor is in range 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 Sensor a. Inspect sensor and connector. Verify that there is no damage to sensor, and no damage, moisture or corrosion in connector. b. Check sensor resistance. (Refer to Note 3 in Section 7.2) 90,000 Ohms @ 77°F (25°C). Refer to Section 8.9.16 for chart of resistances for different sensors. 2. Check Sensor Wiring a. Inspect connector pins and terminals 1-3MSM-13 and 25 (see wiring schematic). Verify that there is no physical damage to harness, and no damage, moisture or corrosion in connectors. b. Place the system in PC mode. Refer to Note 2 in Section 7.2. Disconnect sensor from harness. Check for 3.0 ± 0.1 VDC volts at harness plug between pins. This verifies microprocessor output and wiring connections to the sensor.