Nordyne Two Stage R-410A Split System User's Information/Installation Instructions page 10

Status LED Status LED Description
Green "POWER" Module has power
Red "TRIP" Thermostat demand signal
Y is present, but the
compressor is not
running
Yellow "ALERT" Long Run Time
Flash Code 1 Compressor is
running extremely
long run cycles
Yellow "ALERT" System Pressure Trip
Flash Code 2 Discharge or suction
pressure out of limits or
compressor overloaded
Yellow "ALERT" Short Cycling
Flash Code 3 Compressor is running
only briefly
Yellow "ALERT" Locked Rotor
Flash Code 4
10
Supply voltage is present at module terminals
1. Compressor protector is open
• Check for high head pressure
• Check compressor supply voltage
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
6. Compressor contactor has failed open
1. Low refrigerant charge
2. Evaporator blower is not running
• Check blower relay coil and contacts
• Check blower motor capacitor
• Check blower motor for failure or blockage
• Check evaporator blower wiring and connectors
• Check indoor blower control board
• Check thermostat wiring for open circuit
3. Evaporator coil is frozen
• Check for low suction pressure
• Check for excessively low thermostat setting
• Check evaporator airflow (coil blockages or return airfilter)
• Check ductwork or registers for blockage
4. Faulty metering device
• Check TXV bulb installation (size, location and contact)
• Check if TXV/fixed orifice is stuck closed or defective
5. Condenser coil is dirty
6. Liquid line restriction (filter drier blocked if present in system)
7. Thermostat is malfunctioning
• Solenoid plug not connected
• Y2 not wired at Comfort Alert
8. Thermostat is malfunctioning
• Check thermostat sub-base or wiring for short circuit
• Check thermostat installation (location, level)
9. Comfort Alert failure
1. High head pressure
• Check high pressure switch if present in system
• Check if system is overcharged with refrigerant
• Check for non-condensable in system
2. Condenser coil poor air circulation (dirty, blocked, damaged)
3. Condenser fan is not running
• Check fan capacitor
• Check fan wiring and connectors
• Check fan motor for failure or blockage
4. Return air duct has substantial leakage
5. If low pressure switch present in system, check Flash
Code 1 information
1. Thermostat demand signal is intermittent
2. Time delay relay or control board defective
3. If high pressure switch present go to Flash Code 2 information
4. If low pressure switch present go to Flash Code 1 information
1. Run capacitor has failed
2. Low line voltage (contact utility if voltage at disconnect is low)
• Check wiring connections
3. Excessive liquid refrigerant in compressor
4. Compressor bearings are seized
• Measure compressor oil level
Table 1. Interpreting the Diagnostic LEDS
Status LED Troubleshooting Information