230v Brown-Out Protection Defeated
The brownout feature can be defeated if needed for severe noisy power conditions. This defeat should always be a last resort to solving the problem. Defeat is available on the User Interface setup screen (available with SYSTXBBUID01-C UI) or can be initiated through the forced defrost pins for non-communicating systems as follows:
The brownout toggle is accomplished by shorting the defrost pins from power up with the OAT and OCT sensor connector removed. After 3 seconds, the status of the force defrost short and the OAT/OCT as open will be checked. If correct, then the brownout will be toggled.
SStatus code 6 shows the brownout is disabled. S Status code 5 shows the brownout is active.
After the brownout defeat is set, power down and reinstall the OAT/OCT sensor and remove the short from the forced defrost pins. As long as the short on the forced defrost remains, the OAT and OCT faults will not be cleared. The code will continue to be flashed.
The control is shipped with the brownout active. The change in status is remembered until toggled to a new status. A power down/power up sequence will not reset the status. It may be necessary to do the toggle twice to cycle to the desired state of the defeat.
230V Line (Power Disconnect) Detection
If there is no 230v at the compressor contactor(s) when the indoor unit is powered and cooling or heating demand exists, the appropriate fault code is displayed. Verify the disconnect is closed and 230v wiring is connected to the unit.
Compressor Voltage Sensing
The control board input terminals labeled VS, VR and L2 on 286A/187ANA models and VS and L2 on 288ANA/180ANA models (see Fig. 37) are used to detect compressor voltage status and alert the user of potential problems. The control continuously monitors the high voltage on the run capacitor of the compressor motor. Voltage should be present any time the compressor contactor is energized and voltage should not be present when the contactor is de-energized.
Contactor Shorted Detection
If there is compressor voltage sensed when there is no demand for compressor operation, the contactor may be stuck closed or there may be a wiring error. The control will flash the appropriate fault code.
286A Models - Compressor Thermal Cutout
The control senses the compressor voltage at VR and VS. When starting or running, a phase difference of the voltages on the inputs will indicate the thermal protector is closed. If the phase difference is 5_ or less for 10 seconds, the internal protector is open. The control de-energizes the appropriate compressor contactor for 15 minutes, but continues to operate the outdoor fan. The control Status LED will flash the appropriate code shown in Table 17. After 15 minutes, with a call for low or high stage cooling or heating, the appropriate compressor contactor is energized. If the thermal protector has not re-set, the outdoor fan is turned off. If the call for cooling or heating continues, the control will energize the compressor contactor every 15 minutes. If the thermal protector closes, (at the next 15 minute interval check) the unit will resume operation.
If the thermal cutout trips for three consecutive cycles, then unit operation is locked out for 4 hours and the appropriate fault code is displayed.
288ANA Compressor Thermal Cutout
If the control senses the compressor voltage after start-up and is then absent for 10 consecutive seconds while cooling or heating demand exists, the thermal protector is open. The control de-energizes the compressor contactor for 15 minutes, but continues to operate the outdoor fan. The control Status LED will flash the appropriate code shown in Table 17. After 15 minutes, with a call for low or high stage cooling or heating, the compressor contactor is energized. If the thermal protector has not re-set, the outdoor fan is turned off. If the call for cooling or heating continues, the control will energize the compressor contactor every 15 minutes. If the thermal protector closes, (at the next 15 minute interval check) the unit will resume operation.
If the thermal cutout trips for three consecutive cycles, then unit operation is locked out for 4 hours and the appropriate fault code is displayed.
Low or High Contactor Open (286A models) / No 230V at Compressor Contractor (288ANA models)
If the compressor voltage is not sensed when the compressor should be starting, the appropriate contactor may be stuck open or there is a wiring error. The control will flash the appropriate fault code. Check the contactor and control box wiring.
286A Models Only - Compressor Start Detection on Models with Bristol Compressors Only
In low stage, if the specified start voltage at VR terminal is not achieved, the start relay is de-energized after 1 second and the control will flash the appropriate fault code.
In high stage, if the specified start voltage at VS terminal is not achieved, the start relay is de-energized after 1 second and the control will flash the appropriate fault code.
If the specified start voltage is not achieved for 3 consecutive low stage starts, low stage operation is locked out for 30 minutes. If the specified start voltage is not achieved for 3 consecutive high stage starts, high stage operation is locked out for 30 minutes. The control will flash the appropriate fault code.
Troubleshooting 286A units for proper switching between low & high stages
Check the suction and liquid pressures at the service valves. Suction pressure should be reduced by 5-10% when switching from low to high capacity. There should be a 10-20% increase in liquid pressure when switching from low to high capacity. Compressor current should increase 100-250% when switching from low to high stage.
Troubleshooting 288ANA units for proper switching between low & high stages
Check the suction pressures at the service valves. Suction pressure should be reduced by 3-10% when switching from low to high capacity.
NOTE: The liquid pressures are very similar between low and high stage operation, so liquid pressure should not be used for troubleshooting.
Compressor current should increase 20-45% when switching from low to high stage. The compressor solenoid when energized in high stage, should measure 24vac.
When the compressor is operating in low stage the 24v DC compressor solenoid coil is de-energized. When the compressor is operating in high stage, the 24v DC solenoid coil is energized. The solenoid plug harness that is connected to the compressor HAS an internal rectifier that converts the 24v DC signal to 24v AC. DO
NOT INSTALL A PLUG WITHOUT AN INTERNAL RECTIFIER.
