HVAC Cheat Sheethvaccheatsheet.com/charts/heat-pump-codes/amana-avzc20
Goodman / Amana AVZC20 Heat Pump Codes
The AVZC18 uses a shorter list and an indoor EEV where this series uses a TXV; see its own chart. Other Goodman, Amana and Daikin inverter outdoor units vary by model.
| Code | Meaning | What to check |
|---|---|---|
| E11 / 11 | Run system test (RUN SYS TEST). | Message only. The system test is incomplete or still running. Run EQUIP TEST and SYSTEM TEST from the ComfortNet thermostat's menu; the display clears when testing is complete. |
| E12 / 12 | Outdoor control failure 1 (OD CTRL FAIL1): general memory error. | High electrical noise or a faulty control board. Replace the control board if necessary. |
| E13 / 13 | High pressure, critical (HI PRESSURE C): frequent high pressure faults. | Blocked or restricted condenser coil or lines, stop valve not completely open, overcharge, outdoor fan not running, high pressure switch inoperable, faulty TXV, faulty control board. How to fix → |
| 14 | High pressure, minor (HI PRESSURE M). | Shown at the thermostat only (ClimateTalk code 14); nothing on the outdoor board display. The control has decided the unit can keep running. Same causes as E13. How to fix → |
| E15 / 15 | Low pressure, critical (LOW PRESSURE C): frequent low pressure faults. | Stop valve not completely open, restriction in refrigerant lines, low charge, refrigerant leak, low pressure sensor inoperable or not connected, indoor fan motor not working correctly, faulty TXV, faulty control board. How to fix → |
| 16 | Low pressure, minor (LOW PRESSURE M). | Shown at the thermostat only (ClimateTalk code 16); nothing on the outdoor board display. The control has decided the unit can keep running. Same causes as E15. How to fix → |
| E17 / 17 | Compressor failure (COMPRESSOR FAIL): frequent compressor faults. | Stop valve not completely open, compressor wire has lost a phase, compressor motor failure. Check the wiring between the control board and compressor. How to fix → |
| E18 / 18 | Outdoor control failure 2 (OD CTRL FAIL2): the control board may need to be replaced. | Outdoor fan motor not connected properly, faulty control board, or electrical noise. Check wiring from the outdoor fan motor to the control board first. |
| E19 / 19 | PCB or fan failure (PCB OR FAN FAIL): frequent outdoor control board and/or motor faults. | Obstruction in fan rotation, outdoor fan motor not connected properly, outdoor fan not running, faulty control board, or electrical noise. Check and clean the grille of any debris. How to fix → |
| E20 / 20 | EEV open circuit (EEV OPEN CKT). | Outdoor EEV coil not connected, or faulty outdoor EEV coil. |
| E21 / 21 | EEV control failure (EEV CTRL FAIL): frequent low discharge superheat faults. | Thermistors inoperable or improperly connected, faulty TXV, faulty outdoor EEV or EEV coil, overcharge, faulty pressure sensor, faulty control board. |
| E22 / 22 | High discharge temperature (HI DISCH TEMP). | Discharge thermistor inoperable, improperly connected or out of position; low refrigerant charge; overcharge; faulty compressor. How to fix → |
| E23 / 23 | Discharge temperature sensor failure (DISCH TEMP FAIL): sensor out of range. | Discharge thermistor inoperable or improperly connected. Check its resistance and connections. |
| E24 / 24 | High pressure switch open (HPS OPEN). | High pressure switch inoperable. Check resistance on the switch to verify operation. |
| E25 / 25 | Outdoor air sensor fault (AIR SENSOR FLT): sensor open or shorted. | Faulty outdoor thermistor or disconnected. |
| E26 / 26 | Pressure sensor (PRESSURE SENSOR): sensor not reacting properly. | Low pressure sensor inoperable or not properly connected. |
| E27 / 27 | Outdoor defrost sensor failure (COIL TEMP FAIL1): sensor out of range. | Outdoor defrost thermistor inoperable or not properly connected. How to fix → |
| E28 / 28 | Outdoor coil temperature sensor failure (COIL TEMP FAIL2): sensor out of range. | Outdoor coil thermistor inoperable or not properly connected. |
| E29 / 29 | Liquid temperature sensor failure (LIQ TEMP FAIL): sensor out of range. | Liquid thermistor inoperable or not properly connected. |
| E30 / 30 | Outdoor control failure 3 (OD CTRL FAIL3): the control board may need to be replaced. | Wiring to the control board disconnected, faulty control board, or electrical noise. Check wiring first. |
| E31 / 31 | High leakage current (HI LEAK CURRENT): high leakage current (high voltage) detected. | Improper ground, or faulty compressor. Check ground screws, lugs and wiring. How to fix → |
| E32 / 32 | High temperature on the outdoor control board (HI TEMP CTRL1). | Ambient too high; outdoor fan on low speed (5 ton only); on 2-4 ton units: cooling bracket screws missing or loose, no or poor thermal grease between the cooling plumbing and bracket on the control board, no or limited flow through the board cooling circuit (restriction or low refrigerant), or stop valve not completely open. |
| 33 | High temperature on the outdoor control board, minor (HI TEMP CTRL2). | Shown at the thermostat only (ClimateTalk code 33); nothing on the outdoor board display. The control has decided the unit can keep running. Same causes as E32. |
| E34 / 34 | Current spike (CURRENT SPIKE): high current, potential short circuit. | Current spike in supply, stop valve not completely open, compressor wire has lost a phase, faulty control board, faulty compressor. How to fix → |
| E35 / 35 | High current (HIGH CURRENT). | Short circuit condition, stop valve not completely open, overcharge, faulty control board, faulty compressor. Check installation clearances. How to fix → |
| E36 / 36 | Startup error (STARTUP ERROR): abnormal condition during startup. | Blocked or restricted condenser coil or lines, compressor wire has lost a phase, inconsistent compressor load, faulty control board. |
| E37 / 37 | Outdoor control failure 4 (OD CTRL FAIL4): the control board may need to be replaced. | Outdoor fan motor not connected properly, or faulty control board. Check wiring from the outdoor fan motor to the control board first. |
| E38 / 38 | Compressor voltage (COMP VOLTAGE): voltage issue with the compressor. | High or low supply voltage, compressor wire has lost a phase, faulty control board. |
| E39 / 39 | Outdoor control failure 5 (OD CTRL FAIL5): the control board may need to be replaced. | Thermistors inoperable or improperly connected, or faulty control board. Check thermistor connections first. |
| E40 / 40 | Compressor mismatch (COMP MISMATCH): compressor requirement differs from compressor capability. | Memory card not correct, or control board mismatch. Check memory card data and control board size against the unit model. |
| E41 / 41 | Low refrigerant (LOW REFRIGERANT). | Refrigerant leak, low charge, or thermistors inoperable or not properly connected. How to fix → |
| E42 / 42 | Low line voltage (LOW LINE VOLT). | Low supply voltage. Check breakers and fuses and that the supply matches the rating plate. |
| E43 / 43 | High line voltage (HIGH LINE VOLT). | High supply voltage. Verify the supply matches the rating plate. |
| E44 / 44 | Operating temperature range (OP TEMP RANGE): outdoor temperature outside the recommended range. Unit may continue to operate normally. | Ambient too high or too low. Cycle power and retry within the usable ambient range. |
| E45 / 45 | No cooling test (NO COOLING TEST): cooling mode test can't start because indoor heat is on. | Heat from a secondary heating source. Turn the heater off at the thermostat before running the test. |
| E46 / 46 | No heating test (NO HEATING TEST): heating mode test can't start because indoor heat is on. | Heat from a secondary heating source. Turn the heater off at the thermostat before running the test. |
| E47 / 47 | No system verification test (NO SYS VER TEST): test can't start because indoor heat is on. | Turn the heater off at the thermostat first. |
| E48 / 48 | No pump down (NO PUMP DOWN): pump down mode can't start because indoor heat is on. | Turn the heater off at the thermostat first. |
| E49 / 49 | No charge mode (NO CHARGE MODE): charging mode can't start because indoor heat is on. | Turn the heater off at the thermostat first. |
| E50 / 50 | Line voltage control (LINE VOLT CTRL): voltage issue on the control board. | High or low supply voltage, or faulty control board. |
| E51 / 51 | Outdoor communication error (OD COMM ERROR). | Communication wiring disconnected. Check communication wiring. How to fix → |
| 52 | Compressor failure, minor (COMP FAIL MINOR). | Shown at the thermostat only (ClimateTalk code 52); nothing on the outdoor board display. The control has decided the unit can keep running. Stop valve not completely open, compressor wire has lost a phase, or compressor motor failure. How to fix → |
| 53 | PCB or fan failure, minor (PCB PR FAN MIN). | Shown at the thermostat only (ClimateTalk code 53); nothing on the outdoor board display. The control has decided the unit can keep running. Obstruction in fan rotation, outdoor fan motor not connected properly, outdoor fan not running, faulty control board, or electrical noise. How to fix → |
| 54 | EEV minor (EEV MINOR): frequent low discharge superheat faults. | Shown at the thermostat only (ClimateTalk code 54); nothing on the outdoor board display. The control has decided the unit can keep running. Thermistors inoperable or improperly connected, faulty TXV, faulty control board. |
| 55 | High discharge temperature, minor (HI DIS TEMP MIN). | Shown at the thermostat only (ClimateTalk code 55); nothing on the outdoor board display. The control has decided the unit can keep running. Same causes as E22. How to fix → |
| 57 | Cooling loop sweat (CL LOOP SWEAT): sweating sensed on the control board cooling loop. | Shown at the thermostat only (ClimateTalk code 57); nothing on the outdoor board display. The control has decided the unit can keep running. Refrigerant leak, low charge, faulty TXV, thermistors inoperable or improperly connected. |
| Eb0 | No indoor airflow (NO ID AIRFLOW): estimated airflow from the indoor unit is near 0 CFM. | Failed indoor blower motor, indoor fan motor not properly connected, or too much static pressure. How to fix → |
| Eb9 | Low indoor airflow (LOW ID AIRFLOW): estimated airflow is lower than required. | Failed indoor blower motor, indoor fan motor not properly connected, or too much static pressure. How to fix → |
| Ed0 | No network data (NO NET DATA): the control board doesn't have the data it needs. | Wired as part of a communicating system and the integrated control module contains no shared data. Re-write shared data using the memory card, or replace the control board if necessary. |
| Ed1 | Invalid data (INVALID DATA). | The integrated control module contains invalid shared data, or network data is invalid for it. Re-write shared data using the memory card, or replace the control board if necessary. |
| Ed2 | Invalid system (INVALID SYSTEM): airflow requirement is greater than the indoor unit can deliver. | Outdoor unit needs more airflow than the indoor unit's capability, shared data incompatible or missing parameters, or loose communication wiring. |
| Ed3 | Invalid configuration (INVALID CONFIG): mismatch between the shared data and the control's physical hardware. | Shared data sent to the integrated control module doesn't match the hardware configuration. Verify shared data is correct for the model and repopulate if required. |
| Ed4 | Invalid memory card data (INVALID MC DATA): the memory card data has been rejected. | Verify shared data is correct for the model and repopulate if required. |
How to read the codes
- The outdoor board shows the present fault as E plus two characters, for example E13. The ComfortNet thermostat shows the same fault as a number and a short message (13, HI PRESSURE C).
- A few faults are minor: the control has decided the unit can keep running, and they appear at the thermostat only, with nothing on the outdoor board. They are listed here by their thermostat number. Codes that show both ways are listed as board code / thermostat number.
Codes point to a circuit, not a part. Test before replacing anything, and never jumper a pressure switch to keep a unit running. Line-voltage work is for trained technicians, and refrigerant work requires EPA 608 certification.
Source: Amana AVZC20 Heat Pump Installation & Service Reference, Troubleshooting, pp. 33-36. The "meaning" column follows the manufacturer's wording; "what to check" is our field summary. Always go by the label on the unit you're working on.
Related
- How the heat pump defrost cycle works
- Checking heat pump charge in heat mode
- Look up any heat pump code
Other brands
One field tip a week
A short, practical HVAC tip in your inbox every week: diagnostics, charging, airflow and code changes. Free, unsubscribe anytime.
We'll only use your email for the newsletter. Privacy policy.
HVAC Cheat Sheet · Free PT charts, code lookups and calculators for techs at hvaccheatsheet.com