Here you can find the tables showing possible issues which you may have with Nordyne heat pump. These situations often cause interruptions or lead to heat pump not working. There are several lists – each model of Nordyne has its separate table.
These descriptions tell you about the probable reasons of heat pump not cooling. The descriptions include the flash codes and colors of lights. A separate column includes the recommendations what to do in case of heat pump fan not spinning, or some other situations.
Troubleshooting information is more important for the specialists on repair, but can also be helpful for users in case of small breakdowns.
Nordyne R-410A Heat Pump Troubleshooting
Status LED | Status LED Description | Status LED Troubleshooting Information |
---|---|---|
Green "POWER” | Module has power | Supply voltage is present at module terminals |
Red "TRIP” | Thermostat demand signal Y is present, but the compressor is not running | 1. Compressor protector is open |
2. Outdoor unit power disconnect is open | ||
3. Compressor circuit breaker or fuse(s) is open | ||
4. Broken wire or connector is not making contact | ||
5. Low pressure switch open if present in system & Compressor contactor has failed open | ||
Yellow “ALERT" Flash Code 1 | Long Run Time Compressor is running extremely long run cycles | 1. Low refrigerant charge |
2. Evaporator blower is not running | ||
3. Evaporator coil is frozen | ||
4. Faulty metering device | ||
5. Condenser coil is dirty & Liquid line restriction (filter drier blocked if present in system) | ||
7. Thermostat is malfunctioning | ||
8. Comfort Alert Failure | ||
Yellow “ALERT” Flash Code 2 | System Pressure Trip Discharge or suction pressure out of limits or compressor overloaded | 1. High head pressure |
2. Condenser coil poor air circulation (dirty, blocked, damaged) | ||
3. Condenser fan is not running | ||
4. Return air duct has substantial leakage | ||
5. If low pressure switch present in system, check Flash Codel information | ||
Yellow “ALERT" Flash Code 3 | Short Cycling Compressor is running only briefly | 1. Thermostat demand signal is intermittent |
2. Time delay relay or control board defective | ||
3. If high pressure switch present go to Rash Code 2 information | ||
4. If low pressure switch present go to Flash Code 1 information | ||
Yellow “ALERT" Flash Code 4 | Locked Rotor | 1. Run capacitor has failed |
2. Low line voltage (contact utility if voltage at disconnect is low) | ||
• Check wiring connections | ||
1 Excessive liquid refrigerant in compressor 4. Compressor bearings are seized | ||
• Measure compressor oil level | ||
Yellow “ALERT” Flash Code 5 | Open Circuit | 1. Outdoor unit power disconnect is open |
2. Com pressor circuit breaker or f use(s) is open | ||
3. Compressor contactor has failed open | ||
• Check compressor contactor wiring and connectors | ||
• Check for compressor contactor failure (burned, pitted or open) | ||
• Check wiring and connectors between supply and compressor | ||
• Check for low pilot voltage at compressor contactor coil | ||
4. High pressure switch is open and requires manual reset | ||
5. Open circuit in compressor supply wiring or connections & Unusually long compressor protector reset time due to extreme ambient temperature | ||
6. Compressor windings are damaged | ||
• Check compressor motor winding resistance | ||
Yellow “ ALERT " Flash Code 6 | Open Start Circuit Current only in run circuit | 1. Run capacitor has failed |
2. Open circuit in compressor start wiring or connections | ||
• Check wiring and connectors between supply and the compressor “S” terminal | ||
1 Compressor start winding is damaged | ||
• Check compressor motor winding resistance | ||
Yellow "ALERT” Flash Code 7 | Open Run Circuit Current only in start circuit | 1. Open circuit in compressor run wiring or connections |
• Check wiring and connectors between supply and the compressor “R" terminal | ||
2. Compressor run winding is damaged | ||
• Check compressor motor winding resistance | ||
Yellow “ ALERT " Flash Code 8 | Welded Contactor Compressor always runs | 1. Compressor contactor has failed closed |
2. Thermostat demand signal not connected to module | ||
Yellow "ALERT" Flash Code 9 | Low Voltage Control circuit« 17VAC | 1. Control circuit transformer is overloaded |
2. Low line voltage (contact utility if voltage at disconnect is low) | ||
• Check wiring connections |
Nordyne MT5BD-018K Heat Pump Troubleshooting
Miswired Module Indication | Recommended Troubleshooting Action |
---|---|
Green LED is not on, module does not power up | Determine if both R and C module terminals are connected. Verify voltage is present at module’s R and C terminals. Review 24VAC Power Wiring (page 4) for R and C wiring. |
Green LED intermittent, module powers up only when compressor runs | Determine if R and Y terminals are wired in reverse. Verify module’s R and C terminals have a constant source. Review 24VAC Power Wiring (page 4) for R and C wiring. |
TRIP LED is on but system and compressor check OK | Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below 0.5VAC when off. Verify 24 VAC is present across Y and C when thermostat demand signal is present. If not, R and C are reverse wired. |
TRIP LED and ALERT LED flashing together | Verify R and C terminals are supplied with 19-28VAC. |
ALERT Flash Code 3 (Compressor Short Cycling) displayed incorrectly | Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below 0.5VAC when off. |
ALERT Flash Code 5, 6 or 7 (Open Circuit, Open Start Circuit or Open Run Circuit) displayed incorrectly | Check that compressor run and start wires are through module’s current sensing holes. Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below 0.5VAC when off. |
ALERT Flash Code 8 (Welded Contactor) displayed incorrectly | Determine if module’s Y terminal is connected. Verify Y terminal is connected to 24VAC at contactor coil. Verify 24VAC is present across Y and C when thermostat demand signal is present. If not, R and C are reverse wired. Verify voltage at contactor coil falls below 0.5VAC when off. Review Thermostat Demand Wiring (page 4) for Y and C wiring. |
Nordyne 13 SEER Heat Pump Troubleshooting
Green Led (DS2) | Red Led (DS1) | Mode |
---|---|---|
OFF | OFF | No power to control |
Simultaneous Slow Flash | Simultaneous Slow Flash | Normal operation/ power to control |
Alternating Slow Flash | Alternating Slow Flash | Anti-short cycle lockout |
OFF | Slow FLASH | Low pressure switch fault (Optional) |
OFF | ON | Low pressure switch lockout (Optional) |
Slow FLASH | OFF | High presssure switch fault (Optional) |
OFF | OFF | High pressure switch lockout (Optional) |
Nordyne DLC4(AH)6 Heat Pump Troubleshooting
Error Code on indoor unit | Malfunction | Repair Method/Cause |
---|---|---|
EE | Indoor PCB Malfunction | Replace indoor main board |
E2 | Anti-freeze Protection | Outdoor ambient temperature is too low |
H4 | System overload protection | Check for dirty or blocked heat exchangers |
H6 | Indoor motor malfunction | Check motor mounting and wiring |
F2 | Indoor pipe temperature sensor malfunction | Measure the resistance value in the sensor |
F1 | Return air temperature sensor malfunction | Measure the resistance value in the sensor |
UF | Indoor board malfunction | Replace indoor main board |
H3 | Compressor overload protection | Check overload wiring |
Lc | Compressor start-up failure | Check if the resistance of the compressor and the resistance to ground is normal. If the resistance is normal, the outdoor main board may be defective. |
UH | Outdoor fan motor failure | Check outdoor motor |
E5 | Low voltage protection | Check incoming power |
U7 | 4-way valve malfunction | Replace 4-way valve |
U1 | Compressor phase detection error | Replace outdoor main board |
H7 | Compressor speed reduction | Check if the resistance of the compressor and the resistance to ground is normal. If the resistance is normal, the outdoor main board may be defective. |
U5 | Current detection malfunction | Replace outdoor main board |
F3 | Outdoor ambient temperature sensor malfunction | Measure the resistance value in the sensor |
E4 | Discharge temperature sensor malfunction (out of range) | |
F5 | Discharge temperature sensor malfunction (open or shorted) | |
F4 | Condenser temperature sensor malfunction (open or shorted) | |
P8 | Heat sink over-temperature | Is outdoor ambient temperature out of system operating range? Is heat sink blocked or damaged? |
UU | DC over-current | — |
P7 | Heat sink temperature sensor malfunction | Replace outdoor main board |
FO | Low charge | Check for leaks |
PH | DC input voltage is too high | Check incoming power supply |
PL | DC input voltage is too low | |
E6 | Communication malfunction | Check wiring connection |
UA | Indoor and outdoor unit mismatched | Check system combination |