Lennox 100017 Manual Download Page 36

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Table 2. Alert Codes and Troubleshooting

GF= Gas Furnace, AH=Air Handler, ID=Indoor unit (GF or AH), HP=Heat Pump, AC=Air Conditioner, OD=Outdoor Unit (AC or HP), PA=Pure Air S, ZA=Zone system and TS=Thermostat

Alert

Code

Inverter

Flash

Code

Priority

Condition

Actual Displayed

Alert Text

Under dealer

control center >

Notifications

Component or System Operational State and Troubleshooting Tip

How to clear alert code

434

Service

Soon/Service

Urgent

OD Inverter

Comm Error to

Main Control

• Outdoor control has lost communications with the inverter continuously during a single thermostat

call and one hour period.

• Outdoor control will stop all compressor demands – service soon condition.

• Indoor blower will stop functioning.

NOTE:

Indoor blower will not run in test mode either when alert code 434 is active. Only after

system reset will it operate.

•

This alert code will occur if the outdoor unit power is turned off and the indoor unit power (24VAC

to Lennox outdoor control) remains on, or if the indoor unit power is turned off (24VAC to Lennox

outdoor control) and the outdoor unit power is on. This could occur while performing service or

maintenance procedures on the indoor or outdoor unit.

• The Lennox outdoor control will attempt to re-establish communication to the inverter when the

alert code 434 occurs by cycling the outdoor unit contactor off for two minutes. Upon energizing

the contactor the Lennox outdoor control will attempt to communicate to the inverter for three

minutes. This process will be repeated three times in attempt to establish communication before

locking out.

•

If the unit is locked out with a service soon alert code 434, reset the system by cycling the outdoor

unit power off and back on. Then cycle the indoor power off (24VAC to the Lennox outdoor

control) and then back on.

• If this condition continuously occurs during a one hour period and during a single thermostat call,

the outdoor unit will lock out and display alert code 434 – service urgent condition.

Troubleshooting Options:

•

Check for loose or disconnected electrical connections.

• Interruption of main power to inverter.

•

Inverter LEDs will flash code 53.

• Refer to the unit service documentation for detailed troubleshooting procedures.

Inverter flash code 53.

The sequence is:
•

Red LED: Five Flashes

•

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 system

detects that the issue no longer exists.

If the unit is locked out with a service urgent

alert code 434, reset the system by first

cycling the outdoor unit power off and back.

Then cycle the indoor power off (24VAC to

the Lennox outdoor control) and then back

on.

Summary of Contents for 100017

Page 1: ...T CODE GUIDE V2 Alert Codes Troubleshooting for Communicating Thermostats Indoor and Outdoor Units Lennox Smart Zoning Equipment Interface Module and PureAir S 100017 11 2022 LENNOX SMART THERMOSTAT BASIC COMMUNICATION SYSTEM WIRING AND ALERT CODES ...

Page 2: ...g System Wiring Connections using Unshielded Option 1 or Shielded Wiring Option 2 Cabling There may be situations where alternate wirings methods may need to be employed Two options are available to address an inductive voltage issue If Alert Code 105 see Table 2 Alert Codes and Troubleshooting on page 5 is still present after following troubleshooting Steps 1 and 2 then proceed to Step 3 wiring o...

Page 3: ... C terminal or to second bundle Indoor Unit Controller Outdoor Unit Thermostat R i I C Unused wires Figure 3 Minimizing Electrical Noise 2 Soft Disable Soft disabling is when the Lennox communicating thermostat finds an unknown control on the S30 S40 system communication bus The thermostat sends the unknown control a message to go into soft disable mode until the component is properly configured o...

Page 4: ...pand the description Table 1 Alert Code Priority Condition Visibility Alert Priority Alert Priority Description n Notifications Displayed or Email Notifications Sent Displayed for Homeowner on Thermostat Displayed for Dealer on Thermostat Lennox Smart Thermostat Application Lennox Smart Technician Application LennoxPros Service Dashboard Homeowner Emailed Dealer Emailed Service Urgent Your system ...

Page 5: ... setup was completed S30 Go to menu settings advanced settings view dealer control center equipment and press reset all equipment This will allow the system to auto detect any Lennox communicating devices attached S40 Go to Menu Settings Advanced Settings View Service Support Center Equipment Setting Reset and select Reset Hvac Equipment This will allow the system to auto detect any Lennox communi...

Page 6: ...ge Too Many Devices of the Same Type Check wiring and remove duplicate equipment S30 Go to menu settings advanced settings view dealer control center equipment and press reset all equipment This will allow the system to auto detect any Lennox communicating devices attached S40 Go to Menu Settings Advanced Settings View Service Support Center Equipment Setting Reset and select Reset Hvac Equipment ...

Page 7: ...l continuity If float switch is installed on air handler drain pain check condensate line to ensure it is not clogged and tripping the float switch connected in series with R terminal Check to see if freezestat is installed If fault persists then cycle power Fault clears after communication is restored 32 Information Only Dealer Device Resetting The applicable system component device is resetting ...

Page 8: ...se part number 5KP43CA bidirectional Transorb aka TVS Diode Please con tact your FTC or inside technical support for help in acquiring the transient voltage suppressor if not available in your local electronics store 36 Service Urgent Heating when Not Requested The system has been heating for at least 15 minutes without a demand for heating Run the system in diagnostic mode and verify that it matc...

Page 9: ... Center Diagnostics and select Select All and the secure Start button Check for other alert codes that may be preventing the system from operating as expected Check all heating equipment to determine cause Recycle power Automatically clears when the system detects that the issue no longer exists 39 Service Urgent No Cooling when Requested The system has not been able to turn on the cooling for mor...

Page 10: ...setting S40 Go to Menu Settings Advanced Settings View Service Support Center Equipment Settings Thermostat and located HP Heating Lockout Time to verify the lockout time setting Check air flow to the zones or zones Check discharge air temperatures Check calibration of room thermostat Outdoor Unit and Zoning When the heat pump could not get a zone thermostat to progress 0 5 F towards the set point...

Page 11: ...3 32 2 4 mm tip Check for incorrectly wired or poorly spliced connections between components Verify that low voltage going to system components has been separated from high voltage wiring in wall ceiling floor cavities Check for proper grounding on the line voltage and low voltage wiring transformer and equipment If Alert Code 105 is still present after performing the actions listed above proceed ...

Page 12: ...C Line Voltage The component AC line voltage is too low This alert code may appear during a brownout It may also occur when line voltage is below its designed operating value Check and correct the power line voltage Automatically clears when the system detects the issue no longer exists 111 Service Urgent GF Line Polarity Reversed The unit is reporting that its power and neutral lines are reversed...

Page 13: ... frequency if the system is running on back up power Correct voltage and frequency problems System will resume normal operation five seconds after fault recovered All applicable system component outputs are disabled service soon condition After 10 minutes the priority condition is escalated service critical condition Damper control module will operate in central mode only until the proper voltage ...

Page 14: ...ddressed Automatically clears after an unresponsive system component device responds to any inquiry 124 Service Urgent Tstat Lost Communication To Smarthub The thermostat has lost communication with a system component for more than three minutes Check the wiring connections between components Ohm wires Cycle power Any component that is miss wired may cause a false component code to be shown on sys...

Page 15: ...r from this alert code 180 Service Soon Outdoor Temperature Sensor Problem The thermostat has found a problem with the outdoor sensor in the outdoor unit or the optional outdoor sensor connected to the indoor unit In normal operation after system component control recognizes sensors the alert code will be sent if valid temperature reading is lost Compare outdoor sensor resistance to temperature re...

Page 16: ...stallation instructions Automatically clears after the correct match is detected following a reset 203 Service Urgent ID Invalid Size Unit Code The unit size code for the indoor unit has not been selected or set incorrectly Verify that the correct unit size code is configured Unit size codes for furnace and air handler are listed in the system component configuration guide or installation instruct...

Page 17: ...rvice and Application Note H 13 07 Condensing Furnace Pressure Switch Troubleshooting for additional information Other possible issues that are specific to the older Lennox communicating thermostats are as follows Alert code is generated when a subsequent heating call occurs within 30 seconds of a prior call for heat ending If a call for heat occurs during this time period the inducer post purge f...

Page 18: ...Inspect vent for blockage and combustion air inducer for correct operation and restriction Check for blocked cold end heater box or condensate drain or drain strainers at outlet of cold end heater box Check for cracked hoses Check levelness of unit NOTE Check Service Manual and Service and Application Note H 13 07 Condensing Furnace Pressure Switch Troubleshooting for additional information Automa...

Page 19: ...l ends successfully 250 Service Soon GF Primary Limit Switch Open The furnace primary limit switch is open If limit switch is not closed within three minutes the unit will go into a 60 minute soft lockout Watchguard mode Perform the following Check for high gas pressure Check for low supply air Low supply air due to being plugged or restriction in system example dirty air filter or blockage in duc...

Page 20: ...spect vent for blockages and combustion air inducer for correct operation and restriction Check for blocked cold end heater box CEHB or condensate drain or drain strainers at outlet of CEHB and cracked hoses Check for cracked hoses Check levelness of unit NOTE Check Service Manual and Service and Application Note H 13 07 Condensing Furnace Pressure Switch Troubleshooting for additional information...

Page 21: ... successfully 290 Service Urgent GF Ignition Circuit Fault There is a problem with the furnace ignition circuit The system will go into Watchguard mode Measure resistance of hot surface igniter Replace the hot surface igniter if it is not within specifi cations Automatically clears on successful igni tion 291 Service Urgent GF Heat Airflow Below Min The heating airflow is below the minimum require...

Page 22: ...low Reduce firing rate every 60 seconds to match available CFM Check air filter and duct system To clear replace air filter if needed or repair or add additional duck work Two stage controls will reduce firing rate to first stage Automatically clears when a heating call finishes successfully 312 Information Only Dealer Reduced Airflow Indoor Blower Cutback The indoor blower cannot provide the requ...

Page 23: ...ars after reset and Y1 input sensed 348 Service Soon ID Relay Y2 Fault Possible cause for alert code 348 is Y2 relay on the applicable system component may have failed Lennox communicating thermostat sends a Y2 compressor demand to the indoor control requesting it to relay the demand to the outdoor unit The indoor unit communicating control will verify the presences of 24VAC between the Y1 and C o...

Page 24: ...ize NOTE The air handler will operate on first stage electric heat until the issue is resolved Automatically clears after fault recovered 353 Service Soon AH Electric Heat Stage 3 Fault There is a issue with the air handler s third stage electric heat Either the pilot relay contacts did not close or the relay coil in the electric heat section did not energize NOTE The air handler will operate on f...

Page 25: ...VAC power for two minutes or more on the DS terminal The system will not operate Dealer has cut the W914 jumper Dehum Harmony III on the Lennox furnace control The thermostat monitors the DS terminal in the furnace for power and if the link has been cut then power will be lost to DS If DS to R terminal is accidentally cut you must reconnect a jumper from the DS to R on the terminals strip This ale...

Page 26: ...trips Automatically clears after 30 consecutive normal run cycles or power reset 402 Service Soon OD System Pressure Trip Either the discharge or suction pressure level is out of limits or the compressor has overloaded Check discharge or suction pressure Automatically clears after four consecutive normal compressor run cycles 403 Service Soon OD Compressor Short Cycling The compressor ran for less...

Page 27: ...gh pressure is above the upper limit System will shut down Confirm that the system is properly charged with refrigerant Check condenser fan motor expansion valve if installed indoor unit blower motor stuck reversing valve or clogged refrigerant filter Confirm that the outdoor unit is clean Automatically clears after the high pressure switch closes or a power reset 413 Service Urgent OD High Pressu...

Page 28: ...rge sensor resistance is not within range after 90 second period the control will display the priority condition as service soon If the moderate condition continues for 10 minutes the system changes the priority condition to service urgent Possible Causes The applicable system component detects either an open shorted or temperature out of range condition Discharge sensor leads located in wrong pin...

Page 29: ...output terminal when Y1 out is deactivated Automatically clears once voltage is not sensed on output or power is cycled 422 Service Soon OD Compressor Top Cap Switch Open Compressor top cap switch exceeding thermal limit Check condenser fan motor TXV and indoor unit blower motor Check for stuck reversing valve or clogged refrigerant filter XC XP25 Check to ensure that one of the wires from the top...

Page 30: ...ontrol and restart 427 21 Service Soon Service Urgent OD Inverter DC Peak Fault The inverter has detected a DC peak fault condition If condition 55A or higher is detected outdoor unit will stop compressor and fan service soon condition Anti short cycle is initiated If peak current 55A or higher occurs 10 times within an hour system will lockout service urgent condition Inverter LEDs will flash cod...

Page 31: ...er High Main Input Current The inverter has detected a high main input current condition If condition is detected outdoor unit will stop compressor and fan service soon condition Anti short cycle is initiated If condition occurs 10 times within an hour system will lockout service urgent condition Inverter LEDs will flash code 22 Refer to the unit service documentation for detailed troubleshooting ...

Page 32: ...cle the demand Inverter LEDs will flash code 23 Refer to the unit service documentation for detailed troubleshooting procedures Perform test function and verify inverter DC link and line input voltage and current Also check input to filter board and reactor before replacing inverter board To perform this test go to menu settings advanced settings view dealer control center tests Inverter flash cod...

Page 33: ...26 The sequence is Red LED Two Flashes Green LED Six Flashes NOTE Inverter normal operations with no error code present is as follows Red LED is ON and Green LED is OFF Check refrigerant Replace outdoor control board Replace inverter To clear disconnect power to outdoor unit and restart 431 27 Service Soon Service Urgent OD Inverter PFC Fault The inverter has detected a PFC circuit over current co...

Page 34: ... service urgent condition Inverter LEDs will flash code 28 Refer to the unit service documentation for detailed troubleshooting procedures Inverter flash code 28 The sequence is Red LED Two Flashes Green LED Eight Flashes NOTE Inverter normal operations with no error code present is as follows Red LED is ON and Green LED is OFF Troubleshooting Suggestions Check wire connections U V and W at invert...

Page 35: ...erter automatically increases the compressor minimum speed below 45ºF in the heating mode and above 115ºF ensure the compressor capacity is sufficient for oil return If alert code 433 occurs and inverter does not indicate an inverter code 29 the Lennox communicating Lennox outdoor control triggered the alert code 433 Check the Lennox outdoor control software version by accessing the outdoor unit d...

Page 36: ...ation to the inverter when the alert code 434 occurs by cycling the outdoor unit contactor off for two minutes Upon energizing the contactor the Lennox outdoor control will attempt to communicate to the inverter for three minutes This process will be repeated three times in attempt to establish communication before locking out If the unit is locked out with a service soon alert code 434 reset the ...

Page 37: ...ower to outdoor unit and restart 436 62 Service Soon Service Urgent OD Inverter High Heat Sink Temperature Inverter heat sink temperature exceeded limit This occurs when the heat sink temperature exceeds the inverter limit Inverter will issue inverter alert code 13 first and slow down to try to cool the heat sink If temperature remains high outdoor unit will stop both compressor and fan service so...

Page 38: ...i cally clear when the inverter sends an alert code clear message Service urgent priority condition can be cleared by disconnecting and reconnecting power to outdoor unit to restart 438 73 Service Soon Service Urgent OD Inverter PFC Input Over current The inverter has detected a power factor correction PFC circuit over current condition The inverter has detected an PFC over current condition This ...

Page 39: ... 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 finned aluminium heat sink is located on the back side ...

Page 40: ...tic 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 flash code 14 Refer to the unit service documentation for detailed troubleshooting procedures Inverter flash code 14 Th...

Page 41: ...tes or UV sensor does not respond for more than 5 minutes Device will not perform any UV lamp life remaining calculations until fault has recovered Life remaining display shall indicate while fault exists Automatically clears 30 seconds after fault is recovered 502 Service Soon PA UV Lamp Off The light is determined to be off when the last three last light intensities measurements are below the se...

Page 42: ...o operate in central mode At the Lennox communicating thermostat only zone 1 screen will be available NOTE The Lennox communicating thermostat will display the alert code as Problem Zoning Control Email notifications will describe the issue as Zone X Temp Sensor Problem Automatically clears 30 seconds after condi tion no longer exist 543 Service Soon ZS Zone 2 Temp Sensor Fault 544 Service Soon ZS...

Page 43: ...any to limit the maximum power level usage of the outdoor unit The feature is activated by applying 24VAC power across the L and C terminals on the outdoor control Automatically clears when L terminal is inactive 601 Information Only Dealer OD Unit Low Ambient Operational Lockout Outdoor unit has been cycled off on low temperature protection Outdoor unit will not operate when the outdoor ambient i...

Page 44: ...e no longer exists 703 Service Soon Thermostat Humid Sensor Problem Thermostat Humid Sensor Problem Sensor is damaged or data is corrupted possibly First try a system reset then if persists the thermostat would need replacement 900 Service Soon moderate Temperature Control Problem Something is causing the system not to be able to reach set point Check for dirty coil low refrigerant or verify the s...

Page 45: ... verification failed Update failed Not applicable Automatically clears once is detected for two seconds 65543 Information Only Dealer Firmware Updated When new firmware has been successfully updated to the thermostat Clears automatically after successfully update 65544 Information Only Dealer More Than 8 Tstats In A Group The system is limited to no more than eight 8 smart hubs assigned to one gro...

Page 46: ... home Remove device from thermostat BLE network and replace device Automatically clears when the system detects that the issue no longer exists 70501 Service Soon Custom Sensor Name Internal Data Fault Not able to collect samples communication fault or measured value is out of range from any of the sensor TRH Sensor or Thermistor or occupancy sensor voltage 0 2V or 2 5V then condition is triggered...

Page 47: ...f measured outdoor temperature ODT is not within the expected range No major impact to the system Check and replace sensor if it is failed Automatically clears when the system detects that the issue no longer exists 71509 Information Only Dealer HP Outdoor Coil Temperature Sensor Incorrect Reading If measured outdoor coil temperature ODTCoil T is not within the expected range No major impact to th...

Page 48: ...lly clears when the system detects that the issue no longer exists 80001 Information only Dealer IAQ Persistent Poor Air Quality Cycle power to device If cycling power does not resolve the issue check all installed Indoor Air Quality IAQ equipment installed in the HVAC system For example check All installed IAQ equipment are power on connected and working properly HC air filters and replace if dir...

Page 49: ...al State and Troubleshooting Tip How to clear alert code Service Soon Possible loose incorrectly wired connections or two zone sensors are assigned the same zone number Two dashes will be displayed on the S30 S40 thermostat for indoor temperature and or zone sensor then System will go into central mode Individual zone functions is disabled If two zone sensors are assigned the same zone number this...

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