Digital Compressor Controller Fault Codes - Johnson Controls LSWU Manual

SECTION 8 – SERVICE
DIGITAL COMPRESSOR CONTROLLER
FAULT CODES
The Digital Compressor Controller has a green, yellow
and red LED.
Power LED (Green)
This LED indicates voltage is present at the 24VAC
power terminals. When the two minute anti-short cycle
timer is active, the green LED flashes.
Unloader LED (Yellow)
This LED indicates the status of the unloader solenoid
output. The LED is on when the unloader solenoid is
energized.
Alert LED (Red)
This LED communicates an abnormal system condi-
tion through a unique flash code. The ALERT LED
flashes a number of times consecutively, pause and re-
peat the process. The number of consecutive flashes,
define as the flash Code, correlates to a particular ab-
normal condition. The ALERT code remains active un-
til the reset conditions have been met or 24VAC power
has been cycled OFF and ON to the Digital Compres-
sor Controller.
All the LED's flashing at the same rate indicates
24VAC supply is too low for operation. All LED's on
solid at the same time indicates a Digital Compressor
Controller failure.
Flash Code 2 – High Discharge
Temperature
This code indicates the discharge temperature therm-
istor has measured a temperature above 268.0°F
(130.0 °C) or the thermistor is short circuited (jump-
ered out). See Table 48 on page 197 for resistance to
temperature values.
The Digital Compressor Controller de-energizes the
compressor contactor and unloader solenoid. The com-
pressor is allowed to restart after a 30 minute delay
and after the thermistor temperature is below 250.0°F
(120.0 °C). The flash code is reset after the compressor
has run for 60 uninterrupted minutes without any other
ALERT's.
If five high discharge temperature ALERT's have oc-
curred within four hours, the Digital Compressor Con-
troller locks out the compressor. The lockout can only
be reset by cycling the 24VAC power OFF and ON.
198
Flash Code 3 – Compressor Protector
Trip
This code indicates the demand signal from the Unit
Controller is greater than 1.44VDC and there is no
compressor current detected. This could be due to the
compressor being OFF on internal overload, circuit
breaker open, or power disconnected to the compres-
sor contactor.
The Digital Compressor Controller de-energizes the
compressor contactor and unloader solenoid. The Dig-
ital Compressor Controller waits for the two minute
anti-short cycle timer to time out and if the Unit Con-
troller demand signal is still greater than 1.44VDC,
energize the compressor contactor again. If compres-
sor current is detected on the restart, the ALERT code
resets. The Digital Compressor Controller attempts to
restart the compressor as long as the system controller
demand is above 1.44VDC. There is no lockout feature
for this ALERT.
Flash Code 4 – Locked Rotor
This code indicates a compressor locked rotor condi-
tion is sensed by the Digital Compressor Controller
on four consecutive start ups. The Digital Compressor
Controller de-energizes the compressor contactor and
unloader solenoid, wait two minutes and try to restart
the compressor. If the Digital Compressor Controller
senses a locked rotor condition on the fourth start it
de-energize the compressor contactor and unloader so-
lenoid and lockout the compressor. The 24VAC power
to the Digital Compressor Controller must be turned
OFF and back ON to reset the control.
Flash Code 5 – Demand Signal Loss
This code indicates the demand signal input to the Dig-
ital Compressor Controller dropped below 0.5VDC.
The Digital Compressor Controller de-energizes the
compressor the compressor contactor and unloader so-
lenoid. There is no lockout for this code.
Once the demand signal to the Digital Compressor
Controller rises above 0.5VDC, the ALERT code re-
sets. If the demand signal is above 1.44VDC and the
anti-short cycle timer has timed out, the compressor
restarts.
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
JOHNSON CONTROLS