38GXC(Q)/40GXC(Q) Service Training Sizes 18 and 24K

1. 38GXC(Q)/40GXC(Q) Service Training Sizes 18 and 24K

2. NORMAL OPERATIONS .

3. UNIT PROTECTION .

4. COMPONENT FAILURES .

5. COMPRESSOR FREQUENCY .

6. 18K HEAT PUMP WIRING DIAGRAM .

7. 24K HEAT PUMP WIRING DIAGRAM .

8. 18K COOLING ONLY WIRING DIAGRAM .

9. 24K COOLING ONLY WIRING DIAGRAM .

10. Flow Chart 1– Indoor Freeze Protection No Is system running within operating envelope? System should not be operated Yes Connect low side gauge at suction service valves. Measure discharge temp. OK? No Check for leaks. Yes Yes Clean indoor coil /filter of indoor unit with error message. Problem fixed? Reclaim charge and fix leak. Problem solved No No Check indoor thermistors OK? Replace thermistor Weigh in charge. Yes Check indoor board motor/ thermistor output Output ok? No Replace indoor board. Yes Replace motor .

11. Flow Chart 2 – IPM Protection Check if IPM module voltage between P and N is around 300 V. No No Check power supply to main board. OK? Correct the power supply connection Yes Yes Yes No Check heat sinks on back of board. OK? Problem solved Clean and reattach. Ok? No Yes Confirm there is voltage output and balance between any 2 phases of U,V, and W No Replace main board Yes Replace the compressor .

12. Flow Chart 3 – Compressor Over Current Protection Yes Is unit running in outdoor ambient higher than 110 °F? Beyond operating range No No No Clean coil. Problem persists? Problem solved Outdoor coil clean? Yes Yes Check connections from OD board. Loose, corroded, or high resistance? No Yes Clean/repair connection Problem persists? Replace motor Problem solved Yes No No No Yes Check output on outdoor board. Ok? Outdoor motor ok? Replace outdoor board Yes No No Connect low side gauge at suction service valve. Measure discharge temp.* High head, high suction? High head, low suction? Yes Yes Yes Check amp draw to compressor? Values within range? Unit is overcharged. Reclaim charge and weigh in correct charge. No Restriction in refrigeration circuit. Replace compressor Yes *Measure discharge temperature at the sensor on the discharge tube. Replace outdoor board

13. Flow Chart 4 – High Condensing Temperature Yes Is unit running in outdoor ambient higher than 110 °F? Beyond operating range No No No Clean coil. Problem persists? Problem solved Outdoor coil clean? Yes Yes Check outdoor coil temperature thermistor. Chart 4, ok? No No Replace thermistor. Problem persists Problem solved Yes Yes Yes Check motor for open or short. Ok? Replace outdoor motor No Check output on outdoor board. Ok? No Replace outdoor board

14. Flow Chart 5 – High Compressor Discharge Temperature Connect low side gauge at suction service valve. Measure discharge temp.* Check compressor discharge line thermistor. Ok? Ok No Replace thermistor Yes No No Suction and discharge pressures low? High head, low suction? Yes Yes No Restriction in refrigeration circuit. Check for leaks. Yes Check for blocked capillary tube or a restriction in liquid line Reclaim charge and fix leak. Weigh in charge. *Measure discharge temperature at the sensor on the discharge tube.

15. Flow Chart 6 – High Compressor Temperature Connect low side gauge at suction service valve. Measure discharge temp.* Check compressor Temperature switch Ok? Ok No Replace switch Yes No No Suction and discharge pressures low? High head, low suction? Yes Yes No Restriction in refrigeration circuit. Check for leaks. Yes Check for blocked capillary tube or a restriction in liquid line Reclaim charge and fix leak. Weigh in charge. *Measure discharge temperature at the sensor on the discharge tube.

16. Flow Chart 7 – Temperature Sensor Reset main power and restart system using remote. Problem persists? No No further action is required Yes Check sensor connector at ID or OD board Connection good? No Fix connection Yes No Check input and output on indoor or outdoor board. Replace board Yes No Check sensor resistance. Appendix A4 Replace sensor Yes Double check connection, for corrosion or high resistance.

17. Flow Chart 8 – Communication Error Reset circuit breaker. Is problem fixed? Yes Problem fixed Notes: Before measuring the Volts DC on outdoor TB, disconnect the field wire on terminal S. Before measuring the Volts DC on Indoor TB, disconnect the field wire on terminal S. Have the red probe of the meter on terminal S and the black probe on terminal N. Reconnect wiring when measurements are complete. No Check the wires (type) and connections between Indoor and outdoor units* No Fix connection or replace wiring Yes Reset main power and restart system using remote. Problem persists? No further action is required No Yes Measure Volts DC on outdoor TB between S & L2 (0-24VDC) Ok?** Measure Volts DC on indoor TB between S & L2 (0-24VDC). Ok?** Yes Recheck wiring and connections Yes No No Replace outdoor board. Replace indoor board. . * Thermostat wires cannot be used. Wires should be connected per connection diagrams. Failure to do that will result in a communication error. Polarity needs to be maintained between indoor and outdoor units. ** There is 3 minutes to make the measurement before the diagnostic light comes back on.

18. Flow Chart 9– Indoor Fan Reset main power and restart system using remote. Problem persists? No No further action is required Yes No Check motor connection. Connection good? Fix connection Yes Check IFM output and and input on indoor board. Values good? No Replace indoor board Yes Replace indoor fan motor

19. TEMPERATURE/PRESSURE CHART