Lennox S40 - Page 80

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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
441 14
Information
Only-Dealer
OU Inverter
Compressor Slowdown
- High Compressor
Current
This alert code is for more information than an issue with the system.
• When the inverter gets close to the current or heat sink temperature limit, it will limit the ramp rate. Instead
of changing compressor speed at 1 hz/second, it changes to 5 hz/20 seconds.
• Compressor slowdown due to high compressor current.
• Compressor current is approaching limit.
• The compressor speed automatically slows.
• This error code is primarily for informational purposes as the inverter controls the compressor to operate
within design parameters. Alert code 441 typically occurs at startup as the compressor current increases
rapidly during startup.
• The inverter will reduce the compressor speed by 4 Hz and slow the compressor ramp up speed to the
requested compressor demand speed (capacity). This is normal and expected operation of the inverter to
control the inverter within design parameters. In most cases the alert code 441 notication does not require
any additional service or diagnostic procedures.
• The control sets indoor CFM and outdoor RPM to values according to demand percentage rather than the
actual Hz.
• Possible issue is system running at high pressures.
• Check for high pressure trips or other alert codes in thermostat and outdoor control.
• Inverter LEDs will ash code 14.
• Refer to the unit service documentation for detailed troubleshooting procedures.
Inverter ash code 14.
The sequence is:
• Red LED: One Flash
• Green LED: Four 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.
442
Service
Urgent
OU Compressor Top
Cap Switch Strikes
Lockout
The top cap switch has opened ve times within one hour. As a result, the outdoor unit is locked out
.
• This condition occurs when compressor thermal protection sensor opens ve times within one hour.
• Outdoor unit will stop.
To clear, disconnect
power to outdoor unit
and restart.
443
Service
Urgent
OU MUC Unit Code
To Inverter Model
Mismatch
The Lennox variable capacity unitary control (outdoor control) has incorrect appliance unit size code
selected.
• Check for proper conguring under unit size code used for outdoor unit (see unit conguration guide or in
installation instructions).
• If replacing inverter, verify inverter model matches unit size.
• Remove the thermostat from the system while applying power and reprogramming.
Automatically clears
after the correct match
is detected following a
power reset.
444
Service
Urgent
HP Reversing Valve
Relay or Solenoid Fault
Relay failure. Verify by call for heat pump heating. Check for 24VAC out from O.
Replace Outdoor Unit
Control Board