Maytag PSA4BG024K - Troubleshooting; Inverter Circuit Board LEDs

8
Table 7. Instrumentation List
FUNCTION TYPE CONNECTION
High Pressure
Switch
Opens650±15psig,
recloses460±15psig
See Figure8, and
Figure9
LowPressure
Switch
Opens20±5psig,
recloses35±5psig
IFB*LP1-LP2
Ambient
Air Temp
Thermistor10KΩ @
25°C(Fig.10)
IFB*“OUTDOORTEMP”
(BLK)
Compressor
Discharge Temp
Thermistor10KΩ @
25°C(Fig.10)
IFB*“DISCHARGETEMP”
(RED)
*IFB=InterfaceBoard
Table 6. Interface Board Diagnostic Codes
DISPLAY CAPACITY STAGE
1
Inverter Power Module Overcurrent

GeneralInverterDriveFault

High Compressor Current
4
Current Sampling Error (Inverter)

HighInverterHeatSinkTemperature
6
High DC Bus Voltage (Inverter)
7
LowDCBusVoltage(Inverter)
8
LowLineVoltageatInverter
9
LineOvercurrentatInverter
1
LineVoltageSamplingError(Inverter)
11
LossofCommunication(InverterInternal)
1
InverterHeatSinkSensorFailure
1
LossofCommunication(InverterInternal)
14
LossofCommunication(IFBtoInverter)
1
Override, High Compressor Current
16
Override,HighLineCurrent
17
Override,HighInverterHeatSinkTemp
18
OutdoorFanMotorFault
19
LowPressureSwitchOpen

High Compressor Discharge Temperature
1
Interface Board Software Error

SensorFailure-CompressorDischgTemp
4
SensorFailure-AmbientTemperature
9
CoolingLowTemperatureLockout
TROUBLESHOOTING
The2-characterLEDdisplayontheinvertercontrolboardis
intended to be helpful in diagnosing problems. Under normal
operation, the display will always show both a status indicator
(Table5) along with fault indications (Table 6).
The fault indications are a sequential listing of fault history.
The last 10 fault codes recorded are displayed in sequence,
with the most recent rst. If there is an“active” fault, one
which is currently detected and responsible for interrupting
operation, the right hand decimal point in the display will be
lit,andtherstnumberinthelistwilldouble-blinkatrst,then
appear again. If this decimal point is not lit, all codes listed
are historical only, and none are“active”. Also, if no code
numbers are displayed, there have been no faults recorded,
or the history has been cleared.
NOTE: As standard practice, write down the fault codes in the
history before attempting to clear the history. In troubleshooting,
focusonfaultcodesthatreturnas“active”afterthehistory
has been cleared. Do not replace hardware based on history
alone,i.e.,onfaultsthatarenot“active”.
WARNING:
Do not touch inverter conductors or the tops of
its large capacitors until power has been off for
at least 30 seconds. The inverter will retain a high
voltage for a time after power has been removed.
Failure to comply with this warning could result in
serious injury, death or property damage.
The list of past faults can be cleared by shorting the TEST
pins (J4) at the lower right side of the inverter control board
(when the unit is powered up but not running). This procedure
willalsoforcetheunittobypassthenormal5minutestop-
to-start delay.
Fault and warning codes are listed in Figure 6 (page 13)
and on a label affixed to the inside surface of the control
panel cover.
Inverter Circuit Board LEDs
Forsomeinverter-relatedfaultcodes,itishelpfultonoteat
leastwhetherornotLEDsarelitonthemaininvertercircuit
boards, which are mounted behind the interface board on
whichthecodesaredisplayed.For2,3,and4-tonmodels,
lookforalitLEDabout3inchesdirectlybehindthe2-character
display.Forthe5-tonmodellookforalitLEDabout3inches
directly behind the lower edge of the secondary contactor that
ismountedonthe leftsideoftheuppermounting bracket.
NOTE:ThereareotherLEDsontheinvertercircuitboards
as well as those described above.
FornormaloperationtheinverterLEDslocatedasdescribed
above will blink green slowly. When there is an inverter-
generatedfault,aredLEDnexttothegreenonewillash.
Normally this will be translated into a 2-digit fault code on the
main display.
If the green LED (described above) is not lit, it generally
indicates that line voltage is not getting to the inverter via the
contactor.Checkforthepresenceof208/230voltsbetween
the top two terminals of the main contactor. If voltage is