Lennox S40 - Page 65

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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
370
Service
Urgent
GF Interlock Switch
Open
Communicating Mode:
NOTE: The on-board jumper DS-R (W914) will be cut.
In communicating mode, the DS-R terminal is used with the EL296 and SL280 furnaces and will be used to
monitor a eld-installed interlock switch such as for example a oat switch.
When operating in this capacity, the DS jumper will be monitored as follows:
• When no alert codes are present there will be 24VAC present at this terminal.
• When control see the loss of 24VAC for two minutes it will send an alert code 370 and disable heating
function.
• If currently running a demand it will de-energize all outputs (including the blower).
• In case of an existing interlock switch alert code, upon power reset, an alert code message will be sent if
voltage is not sensed on the DS terminal.
• An alert code clearing message will be sent if 24VAC is sensed on DS terminal for the minimum of 10
seconds.
• The monitoring of DS terminal will apply to both variable speed and constant torque controls.
Non-Communicating Mode:
NOTE: The on-board jumper DS-R (W914) will NOT be cut.
The furnace control has not received 24VAC 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 alert code will
clear when 24VAC is
continuously sensed
on DS terminal for
a minimum of 10
seconds or on a power
reset.
371
Service Soon
/Service
Urgent
AH Float Switch
Sensed Open
After being active for 10 minutes (600 seconds) the priority condition will change to Service Urgent.
Automatically clears
after fault recovered.
380
Service Soon
/Service
Urgent
EIM Interlock Relay
Fault
Interlock relay failure (furnace or air handler modes only).
• Interlock relay is energized, but input is not sensed after three seconds.
• There will be no heating or cooling due to this alert code – service soon condition.
• De-energize interlock relay and energize after ve minutes if demand is still present – service urgent
condition.
Automatically clears
after fault recovered.
381
Service Soon
/Service
Urgent
EIM Interlock Relay
Stuck
Interlock relay stuck (furnace or air handler modes only).
• Interlock relay continuously sensed (with relay off).
• There is no heating and cooling operation – service urgent condition.
• After 10 minutes if event still exist it will be escalated to priority condition service urgent.
Automatically clears
30 seconds after fault
clears.