Nortek YDHA - 7.2 Troubleshooting Compressor Digital Controller

Form O-Y P/N 273647R5, Page 45
Compressor Digital Controller LED’s
7.2 Troubleshooting Compressor Digital Controller
General - The digital controller is located in the electrical compartment and acts as the interface between the digital
compressor and the unit controller. If the unit interface display indicates critical Alarm Code 17, Modulating Capacity
Compressor Failure, check the LED lights on the digital controller.
The alert code (red LED ashes) on the digital controller remains active and the compressor de-energized until the
reset conditions have been met or the 24VAC power is cycled off and on. All Codes except 6 ashes result in com-
pressor (contactor and unloader valve) being de-energized.
LED State
Indicates Additional Information
Color CODE
Green Solid Power (24VAC present at
power terminals)
Modulating capacity compressor starts only when
demand signal input is above 1.45 VDC and no
ALERTS (red LED ashes) are active.
Green. Flashing Anti-short cycle timer is
active
Yellow Solid Unloader (Solenoid valve
is energized; compressor
capacity is 0.)
Modulating capacity compressor always unloads for 0.1
second at startup.
Red Not lit No abnormal operation
alerts
Red 2 Flashes High Discharge
Temperature Alert
(thermistor temperature
above 268°F or
thermistor is short
circuited)
Modulating capacity compressor will be allowed to
restart after a 30-minute delay and after the thermistor
temperature is below 250°F. Compressor will lockout
after 5 alerts within 4 hours and can only be reset by
cycling the 24VAC power off and on.
Red 3 Flashes Compressor Protector
Trip (demand signal
>1.44VDC & no
compressor current)
Possible causes - internal overload, fuse or breaker,
compressor wiring. After 2-minute anti-short cycle timer
the controller will attempt to restart the compressor as
long as demand is above 1.44VDC. No lockout feature.
Red 4 Flashes Locked Rotor Alert Locked rotor sensed by controller on four consecu-
tive start-ups. Lockout occurs and can only be reset by
cycling 24VAC power off and on.
Red 5 Flashes Demand Signal Loss
(below 0.5VDC)
When demand signal input rises above 0.5VDC, alarm
code will reset. When demand reaches above 1.44VDC
and anti-short cycle timer has timed out, modulating
capacity compressor will restart.
Red 6 Flashes Discharge Thermistor
Fault (no signal being
received)
Modulating compressor capacity limited to 50%.
Re-connect or replace thermistor.
Red 7 Flashes Unloader Solenoid Valve
Fault
Red 8 Flashes Compressor Contactor
Fault (compressor
running on less than
1.44VDC demand signal)
Modulating compressor will run unloaded. Alarm will be
reset when current is no longer detected while system
demand signal is below 1.44VDC.
Red 9 Flashes Low 24VAC supply
to controller (below
18.5VAC)
Alarm will reset when supply voltage to controller rises
above 19.5VAC.