Table 27 — Run Test Troubleshooting (VAV Units Only)
PROBLEM | POSSIBLE CAUSE |
Control modules do not have lights when unit power is on. | Transformer open. Circuit breaker open. Power wiring open. Module failure. |
Control display does not light up when unit power is on. | Connection location. Interface cable open. Display failure. |
Run test will not start. | |
| Switch not in local. |
WARN (yellow) LED does not light during run test. | Wiring open. Lamp failure. Control module failure. |
ALARM (red) LED does not light during run test. | Wiring open. Lamp open. Control module failure. |
Run test stops, ALARM (red) LED light is lit after it blinks once. | Bypass switch to LINE. Mode switch to OFF. Duct high |
| pressure switch open. Fire shutdown input or jumper open. |
| Supply air temp out of range. Duct static pressure sensor out of range. |
| Compressor resistor board wiring error or failure. |
Fan does not start/ALARM (red) LED blinks 2 times. | Fan relay failure. |
Run test stop, ALARM (red) LED is lit after blinking 3 times. | Wiring open. VFD connection error. VFD setup error. Fan relay failure. |
| Current isolator failure. Control module failure. |
Run test stop, ALARM (red) LED is lit after it blinks 4 times. | VFD connection error. VFD setup error. |
Fan does not increase speed. | Current isolator load adjustment too low. |
Fan does not stop after ALARM (red) LED blinks 5 times. | Fan relay failure. |
Fan rotation is backwards. | VFD to motor wiring sequence error. VFD setup error. |
Run test stop, ALARM (red) LED is lit after blinking 6 times. | Wiring open. Compressor resistor board wiring error or failure. |
Compressor 1 does not start. | High pressure switch, low pressure switch, coil frost switch, |
| or compressor protection module open. Compressor relay failure. |
| Contactor failure. Control module failure. No refrigerant charge. |
Run test stop, ALARM (red) LED is lit after blinking 7 times. | Wiring open. Compressor resistor board wiring error or failure. |
Compressor 2 does not start. | High pressure switch, low pressure switch, coil frost switch, |
| or compressor protection module open. Compressor relay failure. |
| Contactor failure. Control module failure. No refrigerant charge. |
Run test stop, ALARM (red) LED is lit after blinking 8 times. | Wiring open. Compressor resistor board wiring error or failure. |
Compressor 3 does not start. | High pressure switch, low pressure switch, coil frost switch, |
| or compressor protection module open. Compressor relay failure. |
| Contactor failure. Control module failure. No refrigerant charge. |
Run test stop, ALARM (red) LED is lit after blinking 9 times. | Wiring open. Compressor resistor board wiring error or failure. |
Compressor 4 does not start. | High pressure switch, low pressure switch, coil frost switch, |
| or compressor protection module open. Compressor relay failure. |
| Contactor failure. Control module failure. No refrigerant charge. |
Compressor rotation is backwards. | Field power wiring sequence error. Compressor power wiring sequence error. |
“C” message in I/O status display. | No input signal or communication failure. |
“Service” message in I/O status display. | Value is forced from 6400 keypad entry. |
“Supervisor” message in I/O status display. | Value is forced from network communication (i.e., PC). |
ALARM (red) LED always on, will not enter run test. | SAT, DSP, CSMUX, DHS, or PHASE input values. Mode switch OFF. |
NOTE: For more information on VAV controls, refer to the 50BV,XJ Controls Operation and Troubleshooting Manual.
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