Lennox S40 - Page 79

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Table 21. Lennox S40 Smart Thermostat Alert Codes and Troubleshooting
E2A=Errors to Action, GF= Gas Furnace, AH=Air Handler, IU=Indoor unit (GF or AH), HP=Heat Pump, AC=Air Conditioner, OU=Outdoor Unit (AC or HP), PA=Pure Air S, ZA=Zone system,
SRS=Smart Room Sensor, TS=Thermostat , IAQ- IAQ Monitor and WE=Wi-Fi Extender
Alert
Code
Inverter
Flash
Code
Priority
Condition
Actual Displayed Alert
Text Under dealer control
center > Notications
Component or System Operational State and Troubleshooting Tip
How to clear
alert code
440 13
Information
Only-Dealer
OU Inverter
Compressor Slowdown
- High Heat-Sink
Temperature
Compressor slowdown due to high heat sink temperature.
• Heat sink temperature is approaching limit.
• The compressor speed automatically slows to reduce heat sink temperature.
• The control sets indoor CFM and outdoor RPM to values according to demand percentage rather than the
actual Hz.
• The screws that hold the inverter to the inverter board may be loose causing poor contact between these
two components.
• Tighten screws that hold the heat sink to the inverter control board.
NOTE: Wait ve minutes for all capacitors to discharge before checking screws.
• This error code is primarily for informational purposes as the inverter controls the compressor speed
to operate within design parameters. Typically the inverter will make a minor speed reduction of 4 Hz
(approximately a 5-6% speed reduction) for a brief period of time and to reduce the heat sink temperature
and will then resume normal operation. This may occur at high outdoor temperatures (above 110ºF) for
brief periods of time (3 – 4 minutes) and is normal and expected operation of the inverter controlling the
compressor safely within design parameters.
• The inverter nned aluminium heat sink is located on the back side of the inverter in the condenser air
stream. If the alert code 440 occur frequently, especially at lower outdoor temperatures, check the heat
sink for debris that may reduce heat transfer or possible obstructions that may impact air ow across the
heat sink.
• The inverter will begin to briey reduce the compressor speed when the heat sink temperature rises above
185ºF and will allow the inverter to resume the requested compressor demand speed once the inverter
heat sink reaches 176ºF. The heat sink temperature, compressor speed in Hertz & the Inverter Compressor
Speed Reduction status (“On” or “Off ”) notication can be viewed under the outdoor unit Diagnostics
section of the thermostat dealer control center.
• Inverter LEDs will ash code 13.
• Refer to the unit service documentation for detailed troubleshooting procedures.
Inverter ash code 13.
The sequence is:
• Red LED: One Flash
• Green LED: Three Flashes
NOTE: Inverter normal operations with no error code present is as follows. Red LED is ON and green LED
is OFF.
Automatically clears
when the condition no
longer exists.