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Table 19. Alert Codes and Troubleshooting
Initial notification of critical alerts will pop-up on the home screen and will be listed under notification menu. Minor and moderate alerts are found only under the notification menu. Moderate alerts
are not e-mailed to Homeowners. Dealers will get an email and code can be seen on thermostat under the installer notification section.
NOTE:
Anytime the word
DEVICE
or
DEVICE2
is used in this table, it will be replaced on all alert code notification screens with the actual offending device name, for example, thermostat, heat
pump, etc.).
Alert
Code
Inverter
Flash
Code
Priority
Condition
Applicable
Component
Actual Displayed
Alert Text
Component or System Operational State and Troubleshooting Tip
420
Critical
Air handler
or equipment
interface
module
Defrost Out of
Control
The heat pump defrost cycle has taken more than 20 minutes to complete.
• Defrost cycle lasts longer than 20 minutes.
• Check heat pump operation.
• This is applicable only in communicating indoor unit with non-communicating heat pump.
• Automatically clears when
W1
signal is removed.
421
Critical
Equipment
interface
module and
outdoor unit
W External Mis-
wire Fault
The
W
output terminal on the outdoor unit is not wired correctly. Voltage sensed on
W
output terminal when
Y1
out is
deactivated. Automatically clears once voltage is not sensed on output or power is cycled.
422
Moderate
Outdoor unit
Compressor Top
Cap Switch Open
Compressor top cap switch is exceeding thermal limit.
• Check condenser fan motor, TXV and indoor unit blower motor.
•
Check for stuck reversing valve or clogged refrigerant filter.
•
Lennox Variable Capacity Outdoor Units
: Check to ensure that one of the wires from the top cap switch has not been
disconnected from one of the
TP
terminals on the outdoor control. Reconnect wire if disconnected.
• Check superheat and sub-cooling.
Automatically clears when error is corrected.
423
40
Moderate /
Critical
Variable
capacity
outdoor unit*
OD Inverter CT
Circuit Problem
The inverter has detected a circuit issue.
• When this condition is detected the outdoor control will stop outdoor unit operations and start the anti-short cycle timer –
moderate condition.
• Outdoor control will lockout unit after 10 strikes within an hour – critical condition.
•
Inverter LEDs will flash code 40
•
Refer to the unit service documentation for troubleshooting procedures.
Inverter flash code 40: The sequence is:
Red LED: Four Flashes
Green LED: Off
A moderate alert code will clear automatically when the inverter detects the condition no longer exist and will send a clear alert
code message. To clear critical alert code disconnect power to outdoor unit and restart.
424
Moderate
Outdoor unit
OD Liquid Line
Sensor Faulty
The liquid line temperature sensor has malfunctioned.
•
In normal operation after outdoor control recognizes sensors, the alert code will be sent if a valid temperature reading is lost.
• Compare liquid line sensor resistance to temperature / resistance charts in unit installation instructions.
• Replace sensor pack if necessary.
•
At the beginning of (any) configuration, furnace or air handler control will detect the presence of the sensor(s).
•
If detected (reading in range), appropriate feature will be set as ‘installed’ and shown in the thermostat ‘About’ screen.
Automatically clears upon configuration, or sensing normal values.