230V Brown-Out Protection Defeated; 230V Line (Power Disconnect) Detection; Compressor Voltage Sensing; Contactor Shorted Detection - Bryant Base Series Application Manual And Service Manual

Residential Air Conditioners and Heat Pumps Using R-22 and Puron® Refrigerant: Application Guideline and Service Manual

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.
• Status code 6 shows the brownout is disabled.
• 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, and L2 on 286B/187B and
289B/180B models (see Fig. 44) 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.

Compressor Thermal Cutout

180B/187B/286B/289B

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 18. 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.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Low or High Contactor Open/No 230V at
Compressor Contractor
180B/187B/286B/289B
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.

Troubleshooting units for proper switching

between low & high stages
180B/187B/286B/289B
Check the suction pressures at the service valves.
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 AC signal to 24v DC. DO NOT INSTALL A PLUG
WITHOUT AN INTERNAL RECTIFIER.
Unloader Test Procedure
180B/187B/286B/289B
The unloader is the compressor internal mechanism, controlled by the
DC solenoid, that modulates between high and low stage. If it is
suspected that the unloader is not working, the following methods may
be used to verify operation.
1. Operate the system and measure compressor amperage. Cycle the
unloader on and off at 30 second plus intervals at the UI (from low
to high stage and back to low stage). Wait 5 seconds after staging
to high before taking a reading. The compressor amperage should
go up or down at least 20 percent.
2. If the expected result is not achieved, remove the solenoid plug
from the compressor and with the unit running and the UI calling
for high stage, test the voltage output at the plug with a DC
voltmeter. The reading should be 24 volts DC.
3. If the correct DC voltage is at the control circuit molded plug,
measure the compressor unloader coil resistance. The resistance
should be approximately 330 or 1640 ohms depending on unloader
coil supplier. If the coil resistance is infinite or is grounded, the
compressor must be replaced.
59
Suction pressure