Table 5
System Operation Monitor LED Troubleshooting Codes
Status LED Condition | Status LED Description | Status LED Troubleshooting Information | ||
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Green | Module has power | 24VAC control power is present at the module terminal. | ||
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Green | Module not powering up | Determine/verify that both R and C module terminals are connected | ||
and voltage is present at both terminals. | ||||
OFF |
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| 1. |
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Red | System and compressor | Verify Y terminal is connected to 24VAC at contactor coil. | ||
| check out OK | 2. | Verify voltage at contactor coil falls below 0.5VAC when off. | |
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| 3. | Verify 24VAC is present across Y and C when thermostat | |
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| demand signal is present; if not present, R and C wires are reversed. | |
| Thermostat demand signal | 1. | Compressor protector is open. | |
| Y1 is present, but compres- | 2. | Outdoor unit power disconnect is open. | |
| sor not running | 3. | Compressor circuit breaker or fuse(s) is open. | |
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| 4. | Broken wire or connector is not making contact. | |
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| 5. | Low pressure switch open if present in the system. | |
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| 6. | Compressor contactor has failed to close. | |
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Red | Simultaneous flashing. | Indicates that the control circuit voltage is too low for operation. | ||
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Yellow | Long Run Time − | 1. | Low refrigerant charge. | |
Code 1* | Compressor is running | 2. | Evaporator blower is not running. | |
| extremely long run cycles | 3. | Evaporator coil is frozen. | |
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| 4. | Faulty metering device. | |
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| 5. | Condenser coil is dirty. | |
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| 6. | Liquid line restriction (filter drier blocked if present). | |
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| 7. | Thermostat is malfunctioning. | |
Yellow | System Pressure Trip − | 1. | High head pressure. | |
Code 2* | Discharge or suction pres- | 2. | Condenser coil poor air circulation (dirty, blocked, dam- | |
| sure out of limits or |
| aged). | |
| compressor overloaded | 3. | Condenser fan is not running. | |
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| 4. | Return air duct has substantial leakage. | |
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| 5. | If low pressure switch is present, see Flash Code 1 info. | |
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Yellow | Short Cycling − Compres- | 1. | Thermostat demand signal is intermittent. | |
Code 3* | sor is running only briefly | 2. | Time delay relay or control board is defective. | |
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| 3. | If high pressure switch is present, see Flash Code 2 info. | |
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| 4. | If low pressure switch is present, see Flash Code 1 info. | |
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Yellow | Locked Rotor | 1. | Run capacitor has failed. | |
Code 4* |
| 2. | Low line voltage (contact utility). | |
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| 3. | Excessive liquid refrigerant in the compressor. | |
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| 4. | Compressor bearings are seized. | |
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Yellow | Open Circuit | 1. | Outdoor unit power disconnect is open. | |
Code 5* |
| 2. | Unit circuit breaker or fuse(s) is open. | |
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| 3. | Unit contactor has failed to close. | |
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| 4. | High pressure switch is open and requires manual reset. | |
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| 5. | Open circuit in compressor supply wiring or connections. | |
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| 6. | Unusually long compressor protector reset time due to | |
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| extreme ambient temperature. | |
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| 7. | Compressor windings are damaged. | |
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Yellow | Open Start Circuit − | 1. | Run capacitor has failed. | |
Code 6* | Current only in run circuit | 2. | Open circuit in compressor start wiring or connections. | |
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| 3. | Compressor start winding is damaged. | |
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Yellow | Open Run Circuit − Current | 1. | Open circuit in compressor start wiring or connections. | |
Code 7* | only in start circuit | 2. | Compressor start winding is damaged. | |
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Yellow | Welded Contactor − | 1. | Compressor contactor failed to open. | |
Code 8* | Compressor always runs | 2. | Thermostat demand signal not connected to module. | |
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Yellow | Low Voltage − Control | 1. | Control circuit transformer is overloaded. | |
Code 9* | circuit <17VAC | 2. | Low line voltage (contact utility). | |
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*Flash code number corresponds to a number of LED flashes, followed by a pause, and then repeated. Reset ALERT flash code by removing 24VAC power from monitor; last code will display for 1 minute after monitor is powered on.
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