Lennox Core Unit Controller Setup Manual page 5

LED Status
Green
Green
Heartbeat (HB)
(D33)
No light
Green
BUS (green)
S-BUS / PC
Connection (D70
and D71)
TX (yellow)
Thermostat Input Yellow
MODBUS Two LEDs that indicate transmit (TX) and receive (RX) activity.
Slow Flash = 1 second on; 1 second off.
Fast Flash = ½ second on; ½ second off.
A "flickering" LED flashes significantly faster than a "fast flash".
NOTE: LEDs are energized by 24VAC thermostat inputs.
F. LOCAL INTERFACE - PUSH bUTTONS AND HEART
G. LOCAL INTERFACE - FOUR CHARACTER SEVEN
SEGMENT LED - STATUS CODES
Table 2.
Status
Definition
Code
Pre-Install
PnSt
Smoke
A173
Controller Lockout
LoUt
Off On Alarm
Eror
Delay up to 5 minutes
d300
Delay up to 20 seconds
d020
Dehumidification
dhUM
Compressor Load Shedding
ShEd
Morning Warmup
Prht
Start up
Strt
Fresh Air Heating
FAh
Table 1.
Indication Meaning
Slow Flash Normal Operation
Fast Flash Boot loader / firmware update mode
Steady Off No voltage to M3 board or defective board
Steady On Unit in configuration / test mode (not in normal mode)
Flickering
Network traffic present
ON
Flickering
Unit controller is transmitting
ON
G - Blower on
W1 - First-Stage Heating
W2 - Second -Stage Heating
Indicates a
thermostat Y1 - First-Stage Cooling
demand
Y2 - Second-Stage Cooling
OCP - Occupied
GLO - Global input
Figure 2. Push buttons and Heart beat
Status Codes
LED Operation Indicators
bEAT
Status
Definition
Code
Heating (50%)
h050
Pre-Cool
PrCL
Cool + Max Open Economizer
CEoP
Cool + Modulate Economizer (10%)
CE10
Free Cooling
FrCL
Fresh Air Cooling
FAC
Cooling (78%)
CO78
Blower On - (71.5%) OAS
671S
Blower On (23%)
623
No Demand - OAS
ioAS
No Demand
idLE
5
Table 2. Status Codes